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The effects of pre-existing dementia on surgical outcomes in emergent and nonemergent general surgical procedures: assessing differences in surgical risk with dementia

BMC Geriatrics201818:153

https://doi.org/10.1186/s12877-018-0844-x

Received: 24 January 2018

Accepted: 25 June 2018

Published: 3 July 2018

Abstract

Background

The aim was to assess the morbidity and in-hospital mortality that occur in surgical patients with pre-existing dementia compared with those outcomes in non-dementia patients following emergent and nonemergent general surgical operations.

Methods

A total of 120 patients with dementia were matched for sex and type of surgery with 120 patients who did not have dementia, taken from a cohort of 15,295 patients undergoing surgery, in order to assess differences in surgical risk with dementia. Patient information was examined, including sex, body mass index (BMI), prevalence of individual comorbidities at admission, and several other variables that may be associated with postoperative outcomes as potential confounders.

Results

Patients with dementia tended to have a higher overall complication burden compared to those without. This was evidenced by a higher average number of complications per patient (3.30 vs 2.36) and a higher average score on the comprehensive complication index (48.61 vs 37.60), values that were statistically significant for a difference between the two groups. The overall in-hospital mortality in patients with dementia was 28.3% (34 deaths out of 120 patients). During the same period, at our hospital, the overall in-hospital mortality in the control group was 20% (24 deaths out of 120 patients). Patient groups with and without dementia each had 3 and 5 associated risk factors for morbidity and 9 and 12 risk factors for mortality, respectively.

Conclusions

Patients with pre-existing dementia have a greater than average risk of early death after surgery, and their incidence of fatal complications is higher than that of surgical patients without dementia.

Keywords

  • Dementia
  • Surgical outcomes
  • Morbidity
  • Mortality
  • Predictive factors

Background

Dementia represents a chronic global loss of cognitive or brain function and manifests as the loss of memory, executive function and attention [1, 2]. Although dementia can affect a person at any age, those at most risk are essentially older people. Worldwide, the population aged 80 and older is expected to increase from 126.5 million in 2015 to 446.6 million in 2050 [3].This means that as older age groups increase in size, the global prevalence of dementia in the world population will substantially increase, with estimates suggesting 65.7 million by 2030 and a near doubling to 115.4 million by 2050 [2, 4]. Given these demographic changes, a rise in the potential number of surgical patients with dementia can also be expected. Thus, the demand for the care and treatment of the older patients with dementia and surgical problems is likely to grow in the next years.

Surgical procedures in patients with dementia carry a significant risk of complications and have a high mortality rate. In one recent study [5], surgical mortality for the patient with dementia was 13% in 30 days, increasing with time to as high as 92% in two years, compared with a surgical mortality rate of less than 7% for those without dementia [6, 7]. As the mortality rates for many leading causes of death have declined over the past decade, these high mortality rates for dementia have not improved significantly and may increase further.

Moreover, with a projected survival of 3–12 years from diagnosis, these patients have a shorter life expectancy than those without dementia [810]. Accurate preoperative risk stratification can be difficult because pre-existing dementia that contributes to the early death of such patients is a non-modifiable factor. Thus, the treatment of choice for this group of patients is difficult to determine.

Previous studies dealing with surgical outcomes among patients with pre-existing dementia have concentrated mainly on traumatic patients [1113]. There have been few studies in patient populations with general and vascular surgical conditions and dementia [5, 6, 14], and their findings have not been consistent. There has not been a study, to our knowledge, that compared outcome after surgery among non-traumatic patients with a pre-existing diagnosis of dementia with outcomes among an equal number of operated patients who did not have dementia, matched for sex, type of surgery and with relatively similar patient characteristics and surgical variables. Understanding clinical conditions unique to older adults that affect surgical outcomes is important. Dementia for any reason is currently not part of any routinely performed pre-surgical assessment strategy in general surgery. As a result, little is known about the effects of pre-existing dementia on postoperative outcomes.

This study was done retrospectively. Data have been generated to identify patient-, disease-, and management-related factors that were associated with adverse outcomes in these patients. Its purpose was to evaluate surgical outcomes among non-traumatic patients with pre-existing dementia and to compare these outcomes with those of sex- and treatment-matched controls without dementia in an attempt to identify predictors of morbidity and early death.

Methods

Data from a database of the Department of Transplantation, Thoracic, Visceral and Vascular Surgery of the University of Leipzig were retrospectively analyzed for the years 2011 to 2017. This included review and analysis of data for all studied patients who had been prospectively entered in a data registry, which records patient and disease characteristics and outcomes. Based on the principal operative procedure, all elective or emergent operations were categorized as involving general surgery (GS) and vascular surgery (VS).

Only patients whose procedure warranted more than an overnight stay were selected. All patients with pre-existing dementia (n = 120) who underwent surgery between November 2011 and August 2017 at our center were included in this study. Dementia was defined as any outpatient physician visits or hospital admissions in which dementia was recorded as a diagnosis according to the International Statistical Classification of Diseases and Related Health Problems, tenth edition [ICD-10; F00, F01, F02, F03 or G30]. Patients with mental status changes or delirium in the context of their current illness were not included in this study.

In order to evaluate differences in surgical risk associated with dementia, the 120 patients with dementia were matched for sex and type of surgery with equal number of controls who did not have dementia taken from a cohort of 15,295 surgical patients (Fig. 1). Patient Characteristics (Table 1) and surgical variables (Table 2) that may be associated with postoperative outcomes as potential confounders were examined. In cases of multiple procedures on a patient during hospitalization, only the initial procedure was eligible for inclusion. The main outcome measures were morbidity and in-hospital mortality (End of follow-up was discharge from the hospital, and mortality was defined as hospital death). The severity of medical conditions at the time of surgery was evaluated using the American Society of Anesthesiologists (ASA) Physical Status classification [15]. The Clavien-Dindo classification (CDC) of surgical complications [16] was used to classify surgical complications. In addition, based on CDC at discharge, the comprehensive complication index (CCI) [17] was calculated for each patient in order to evaluate the true overall morbidity burden of a procedure.
Figure 1
Fig. 1

Flow diagram of patient selection

Table 1

Patient characteristics by group

Variable

Dementia group

Non-dementia group

p-value

(n = 120)

(n = 120)

Sex

 Female

71 (59.2)

71 (59.2)

1.00

 Male

49 (40.8)

49 (40.8)

1.00

Age, years, mean ± SD

80.45 ± 9.07

74.06 ± 9.74

.045

BMI, mean ± SD

25.28 ± 5.17

26.78 ± 6.60

.055

COD

 Hypertension

109 (90.8)

100 (83.3)

.083

 Congestive heart failure

46 (38.3)

32 (26.7)

.054

 Ischemic heart disease

27 (22.5)

32 (26.7)

.454

 Cardiac arrhythmia

58 (48.3)

39 (32.5)

.012

 Cardiac valve disease

16 (13.3)

11 (9.2)

.307

 Diabetes mellitus

47 (39.2)

47 (39.2)

1.00

 COPD

20 (16.7)

14 (11.7)

.267

 Chronic renal failure

44 (36.7)

29 (24.2)

.035

 Vascular disease

56 (46.7)

44 (36.7)

.116

 CNS disease

38 (31.7)

18 (15.0)

.002

COD-PP, mean ± SD

4.99 ± 2.39

4.49 ± 2.51

.116

ASA-Classχ

 ASA 1

0 (0.0)

1 (0.8)

.333

 ASA 2

11 (9.2)

23 (19.2)

.044

 ASA 3

70 (58.3)

70 (58.3)

1.00

 ASA 4

23 (19.2)

22 (18.3)

.666

 ASA 5

5 (4.2)

1 (0.8)

.081

PS-PP, mean ± SD

1.33 ± 1.76

1.68 ± 1.94

.144

Disease entity

 Benign

102 (85)

103 (85.8)

.711

 Malignant

18 (15)

17 (14.2)

.711

n total number of patients, SD standard deviation, BMI body mass index, COD Coexisting disease, PP per patient, COPD chronic obstructive lung disease, ASA The American Society of Anesthesiologists Physical Status classification, CNS indicates central nervous system disease and holds for patients with medically documented cerebral vascular accident, transient ischemic attack, or neurological deficit of central origin, PS previous surgery; Numbers in bracket show values presented in n (%) unless noted otherwise. χ, Percents may not total 100 due to missing data

Table 2

Surgical variables by group

Variable

Dementia group

Non-dementia group

p-value

(n = 120)

(n = 120)

Types of surgery

 GS

92 (76.7)

92 (76.7)

1.00

 VS

28 (23.3)

28 (23.3)

1.00

Surgical indications

 Critical limb ischemia

23 ((19.2)

19 (15.8)

.732

 Bowel obstruction

14 (11.7)

12 (10)

.836

 Perforated viscus

13 (10.8)

13 (10.8)

1.00

 Decubitus ulcer

9 (7.5)

6 (5.0)

.595

 Cholecystitis

8 (6.7)

9 (7.5)

1.00

 Cancer GIT

7 (5.8)

7 (5.8)

1.00

 Diverticulitis

6 (5.0)

10 (8.3)

.439

 Hernia

6 (5.0)

8 (6.7)

.784

 Mesenteric ischemia

6 (5.0)

2 (1.7)

.281

 Diabetic angiopathy

5 (4.2)

4 (3.3)

1.00

 Miscellaneous

23 (19.2)

30 (25.0)

.631

Surgical treatment

 Amputation

16 (13.3)

14 (11.7)

.846

 Bowel resection

22 (18.3)

19 (15.8)

.732

 Surgical revascularization

16 (13.3)

16 (13.3)

1.00

 Adhäsiolysis

7 (5.8)

7 (5.8)

1.00

 Major resection HBP

3 (2.5)

3 (2.5)

1.00

 Cholecystectomy

8 (6.7)

9 (7.5)

1.00

 Thyroidectomy

4 (3.3)

4 (3.3)

1.00

 Multivisceral resection

5 (4.2)

4 (3.3)

1.00

 Closure perforated viscus

8 (6.7)

10 (8.3)

.807

 Hernia repair

7 (5.8)

8 (6.7)

1.00

 Procedures thorax

4 (3.3)

4 (3.3)

1.00

 Miscellaneous

20 (16.7)

22 (18.3)

.816

Surgical technique

 Conventional

101 (84.2)

103 (85.8)

.718

 Minimally invasive

17 (14.2)

16 (13.3)

1.00

 Hybrid

2 (1.7)

2 (1.7)

1.00

Urgency

 Emergency

61 (50.8)

57 (47.5)

.606

 Elective

59 (49.2)

63 (52.5)

.606

Classification of OT

 OT < 90 min

58 (48.3)

56 (46.7)

.796

 OT ≥ 90 min

62 (51.7)

64 (53.3)

.796

 OT, mean ± SD

103.78 ± 80.17

119.68 ± 94.93

.162

n total number of patients, GS general surgery, VS vascular surgery, OT operative time; Numbers in bracket show values presented in n (%) unless noted otherwise

Statistical analysis was performed using SPSS software version 24 for windows (IBM Corporation, USA). All statistical tests were 2-sided, and a P value ≤0.05 was considered statistically significant. Descriptive statistics assessed the distribution of patients, procedures, comorbidities, morbidity and mortality by group. Univariate statistical comparisons between groups were performed using Student’s t-test for continuous variables and the chi-square test for discrete variables to examine the univariate relation between preoperative risk factors and outcome variables. Based on the sample size, those risk factors related to morbidity and mortality at a 0.05 significance level were then entered into a multivariate logistic regression analysis, with outcome variables as dependent variables and the risk factors as independent variables, to identify clinical features that were predictive of morbidity and mortality associated with patient groups. This study was approved by the institutional ethics committee review board of the medical faculty of the University of Leipzig in Leipzig, Germany.

Results

The current study reports the relationship between pre-existing dementia and postoperative outcomes. A total of 15,295 patients who had surgery in our hospital from November 2011 to August 2017 were identified. Among these, 240 patients were studied. Stratification by diagnosis yielded 120 patients with pre-existing dementia and a female predominance for undergoing elective and emergent operations in general and vascular surgery. These patients were matched for sex and type of surgery with 120 patients who did not have dementia with a relatively similar distribution of patient characteristics and surgical variables. Almost all variables that define preoperative patient characteristics and surgery were well balanced between the dementia and non-dementia groups. Only 4 of 57 variables (Tables 1 and 2) had a significant difference.

Of the 120 patients with dementia, 71 were female (59.5%). Patients with dementia were older on average (80.5 vs 74.1 years old).

Comorbid conditions that were advanced and stable were present in almost all patients with and without dementia. Their distribution was comparable across both patient groups with the exception of cardiac arrhythmia, chronic renal failure, and CNS disorders, which tended to be more frequent among patients with dementia. Otherwise, no significant dementia-related differences in patient characteristics were observed in the study population. Furthermore, as Table 2 shows, the distributions of the type of surgery, surgical indications, specific type of surgical procedures, surgical techniques, urgency, and mean operative time are relatively similar in both groups.

A summary of surgical outcome data is depicted in Table 3. As this table shows, the occurrence of postoperative complications evaluated using the CDC is not as different, as expected, in the patients with dementia compared to those without dementia and is relatively comparable across both patient groups. In addition, based on the CDC at discharge, the CCI was calculated retrospectively, taking into account all complications after a procedure and their respective severity, in an effort to quantitate and compare the true overall morbidity burden of a procedure. In contrast to the CDC, when we evaluate the true overall morbidity burden of a procedure using the CCI, individuals with dementia tended to have a significantly higher score compared with those without. This indicates a higher overall complication burden in this group. This was also evidenced by a higher average number of complications per patient, which was statistically significant for a difference between the two groups. Moreover, among specific complications, there was a statistically significant difference between patients with and without dementia when we considered the incidence of surgical site infection (SSI), postoperative delirium (PD) and pneumonia. The occurrence of these complications was significantly higher in patients with pre-existing dementia compared to those without.
Table 3

Surgical outcome data by group

Variable

Dementia group

Non-dementia group

p-value

(n = 120)

(n = 120)

Complications

 Bleeding

10 (8.3)

16 (13.3)

.299

 SSI

57 (47.5)

39 (32.5)

.018

 IMDRB

42 (35)

30 (25)

.091

 WDN

11 (9.2)

7 (5.8)

.463

 Bilioma-Bile leakage

2 (1.7)

6 (5)

.281

 Anastomotic leakage

6 (5)

6 (5)

1.00

 Sepsis

21 (17.5)

24 (20)

.864

 RLN Palsy

2 (1.7)

0 (0)

.498

 Hypocalcemia after TX

4 (3.3)

2 (1.7)

.684

 Pneumonia

32 (26.7)

10 (8.3)

<.001

 Thromboembolism

11 (9.2)

12 (10)

.826

 Myocardial infarction

1 (0.8)

2 (1.7)

.561

 ARF

22 (18.3)

23 (19.2)

.869

 CA new

9 (7.5)

7 (5.8)

.605

 Diarrhea

11 (9.1)

7 (5.8)

.424

 TIA, Stroke

3 (12.5)

0 (0)

.156

 Postoperative delirium

39 (32.5)

3 (2.5)

<.001

 Pancreatitis

2 (1.7)

1 (0.8)

.561

 LFRI

28 (23.3)

23 (19.2)

.430

 PERI

21 (17.5)

16 (13.3)

.371

Complications pp, mean ± SD

3.30 ± 2.71

2.36 ± 2.49

.005

CDC

 Grade I

6 (5)

10 (8.3)

.301

 Grade II

27 (22.5)

20 (16.7)

.255

 Grade IIIa

7 (5.8)

7 (5.8)

1.00

 Grade IIIb

17 (14.2)

24 (20)

.230

 Grade Iva

5 (4.2)

3 (2.5)

.472

 Grade IVb

3 (2.5)

0 (0)

.247

 Grade V

34 (28.3)

24 (20)

.132

CCI, mean ± SD

48.61 ± 37.85

37.6 ± 36.32

.022

Admission to ICU

 Yes

73 (60.8)

62 (51.7)

.152

Reoperation

 One

18 (15)

21 (17.5)

.600

 Multiple

22 (18.3)

20 (16.7)

.497

Outcome

 Discharge

86 (71.7)

96 (80)

.132

 Death

34 (28.3)

24 (20)

.132

Cause of death

 MI, cardiogenic shock

0 (0)

1 (4.0)

.414

 Sepsis with mof

18 (52.9)

19 (79.2)

.041

 Decomp. Cardiac GI

8 (23.5)

1 (4.0)

.045

 Malignancy final stage

2 (5.9)

0 (0)

.506

 Unclear

6 (17.6)

3 (12.5)

.722

Place of death

 ICU

14 (38.24)

21 (87.50)

<.001

 Ward

21 (61.76)

3 (12.50)

<.001

Time to death, days

 1–7

14 (41.2)

6 (30.0)

.290

 8–14

5 (14.7)

4 (16.7)

.922

 15–40

10 (21.4)

11 (45.8)

.419

 41–90

2 (5.9)

3 (12.5)

.679

LOS, days, mean ± SD

21 ± 17.98

20.1 ± 16.93

.690

RLN recurrent laryngeal nerve, TX thyroidectomy, WDN wound dehiscence noninfectious, mof multiorgan failure, CA cardiac arrhythmias, ARF acute renal failure, TIA transitory ischemic attack, LFRI lung failure requiring intubation, PERI pleural effusion requiring drainage, PP per patient, CDC Clavien-Dindo classification of complications, CCI comprehensive complication index, MDRB multi-drug-resistant bacteria, LOS length of hospital stay, ICU intensive care unit, SSI surgical site infection defined as being contained within the skin or subcutaneous tissue (superficial), or involving the muscle and/or fascia (deep); Numbers in bracket show values presented in n (%) unless noted otherwise

Furthermore, the presence of dementia was associated with an increased likelihood of being admitted to the ICU. In addition, individuals with dementia were more likely to die within the first 7 days of surgical treatment before leaving the ICU.

For patients with dementia, the overall in-hospital mortality rate was 28.3% (34 of 120). Of these 34 deaths, 23 (67.6%) were associated with emergency operations and 11 (32.6%) with elective operations. In-hospital mortality during the same period was 20% (24 of 120) in the non-dementia group. Of these 24 deaths, 17 (70.8%) were associated with emergency operations and 7 (29.2%) with elective operations. The emergency and elective mortality rates were 37.7 and 18.6% in patients with dementia and 29.8 and 11.1% in the group without dementia, respectively. Thus, the postoperative risk of mortality was more than twofold in patients undergoing emergency operations when compared with those undergoing elective operations.

Overall, morbidity and in-hospital mortality were higher in surgical patients with a pre-existing diagnosis of dementia than in the control group. The associations between risk factors, morbidity and in-hospital mortality calculated with the chi-square test for a linear trend by group are depicted in Tables 4 and 5. We performed multivariate analysis with age, ASA classification, pre-existing cardiac arrhythmia, diabetes mellitus, emergent operations, pulmonary complications and surgical site infection as covariates. In this model, emergent operation, ASA class above 2 and pulmonary complications remained significantly associated with surgical outcome (Table 6).
Table 4

Associations between risk factors and occurrence of postoperative complications calculated with chi-square for linear trend

 

Dementia group (N, 120)

Non-dementia group (N, 120)

 

Occurrence of complication

Occurrence of complication

 

Yes

No

p value

Yes

No

p value

 

n = 100

n = 20

 

n = 89

n = 31

 

Risk factor

 Age ≥ 75 years

81 (81)

11 (55)

.012

47 (52.8)

15 (48.4)

.67

 Congestive herart disease

41 (41)

5 (25)

.179

29 (32.6)

3 (9.7)

.013

 Cardiac arrhythmia

53 (53)

5 (25)

.022

33 (37.1)

6 (19.4)

.070

 Diabetes

40 (40)

7 (35)

.676

41 (46.1)

6 (19.4)

.009

 Kidney disease

37 (37)

7 (35)

.865

26 (29.2)

3 (9.7)

.029

 ASA classification > 2

82 (91.2)

16 (84.2)

.364

76 (87.4)

17 (56.7)

<.001

 Emergent operation

56 (56)

5 (25)

.011

48 (53.9)

9 (29)

.017

Numbers in bracket show values presented in n (%) unless noted otherwise

Table 5

Associations between risk factors and in-hospital mortality calculated with chi-square for linear trend

 

Dementia group (N, 120)

Non-dementia group (N, 120)

 

Outcome

Outcome

 

Survived

Died

 

Survived

Died

 
 

n = 86

n = 34

p value

n = 96

n = 24

p value

Risk factor

 Age ≥ 75 years

61 (70.9))

31 (91.2)

.018

47 (49)

15 (62.5)

.235

 Cardiac arrhythmia

39 (45.3)

19 (55.9)

.298

27 (28.1)

12 (50)

.041

 ASA classification > 2

68 (87.2)

30 (98.3)

.134

69 (74.2)

24 (100)

.005

 Emergent operation

38 (44.2)

23 (67.6)

.021

40 (41.7)

17 (70.8)

.010

 Surgical site infection

40 (46.5)

17 (50)

.730

27 (28.1)

12 (50)

.041

 Sepsis

3 (3.5)

18 (52.9)

<.001

4 (4.2)

20 (83.3)

<.001

 Pneumonia

17 (19.8)

15 (44.1)

.007

4 (4.2)

6 (25)

.001

 Lung failure

8 (9.3)

20 (58.8)

<.001

1 (1)

22 (91.7)

<.001

 Pleural effusion

13 (15.1)

8 (23.5)

.274

8 (8.3)

8 (33.3)

.001

 Pulmonary complication

21 (24.4)

28 (82.4)

<.001

12 (12.5)

21 (87.5)

<.001

 Cardiovascular complication

7 (8.1)

10 (29.4)

.003

8 (8.3)

11 (45.8)

<.001

 Acute renal failure

4 (4.7)

18 (52.9)

<.001

3 (3.1)

20 (83.3)

<.001

 Postoperative delirium

21 (24.4)

18 (52.9)

.003

0 (0)

3 (12.5)

<.001

Numbers in bracket show values presented in n (%) unless noted otherwise; cardiovascular complications indicate the total number of cardiovascular complications and include thromboembolism, myocardial infarction and newly diagnosed cardiac arrhythmias. Pulmonary complications indicate the total number of pulmonary complications and include pneumonia, lung failure requiring intubation and pleural effusion requiring drainage

Table 6

Multivariable Logistic Regression Analyses

 

Dementia group

Non-dementia group

Predictive factors

Odds ratio (95% CI)

p value

Odds ratio (95% CI)

p value

Predictive factors for morbidity by group

 Emergent operations

3.56 (1.0–12.67)

.05

3.20 (1.20–8.55)

.02

 ASA classification > 2

1.15 (0.41–3.22)

.79

.38 (.17–.84)

.02

 Cardiac arrhythmia

2.87 (0.91–9.02)

.07

2.05 (0.68–6.19)

.21

 Diabetes mellitus

.89 (0.30–2.66)

.84

2.77 (0.94–8.21)

.07

 Age ≥ 75 years

0.34 (0.11–1.04)

.06

1.50 (.56–3.92)

.41

Predictive factors for mortality by group

 ASA classification > 2

2.98 (1.22–7.26)

.02

5.18 (1.23–21.83)

.03

 Pulmonary complication

.07 (.02–.23)

<.001

.02 (.002–.09)

<.001

 Wound complication

1.28 (.43–3.84)

.66

.15 (.02–.93)

.04

 Age ≥ 75 years

4.04 (.91–17.90)

.07

2.12 (.40–11.15)

.38

 Cardiac arrhythmia

.96 (.34–2.67)

.94

1.87 (.36–9.73)

.48

 Emergent operation

1.34 (.43–4.54)

.59

0.32 (0.07–1.40)

.13

ASA The American Society of Anesthesiologists Physical Status classification

Discussion

The evaluation of risk factors in predicting outcomes in patients with a diagnosis of pre-existing dementia undergoing a variety of general and vascular surgical procedures was the focus of the current study. The hypothesis was that dementia is a surgical factor distinct from sex, comorbidity, and type of surgery and correlates with morbidity and surgical mortality. To examine this assertion, patients with pre-existing dementia were compared with an equal number of patients without dementia matched for sex and type of surgery. Assuming that the determinants of surgical outcome are multifactorial, we analyzed a number of clinical variables. The main result of this study was that, regardless of the advances made in surgical technique and preoperative and postoperative care, outcomes among dementia patients requiring surgery were relatively poor. Compared to patients who did not have dementia, we observed an increased rate of complications and surgical mortality. Of the 120 consecutive surgical patients with pre-existing dementia treated over a 6-year period, 34 (28.3%) died within 90 days of surgery. Sepsis with multi-organ failure and decompensated cardiac global insufficiency were the most common causes of early death.

Previous studies reporting mortality from different data bases describe early mortality rates of 7–13% for surgical patients with pre-existing dementia [57]. The mortality rate in the current cohort was generally higher in comparison; however, it should be noted that 50.8% of our patients with dementia and 47.5% without were operated on in emergency sessions. Emergent operation has been recognized as a common determinant of in-hospital mortality [18]. This was also observed in the current study, in which almost 68% of early deaths in the dementia group and 71% in the non-dementia group were after emergent operations. This suggests advanced disease processes at the time of admission.

Among comorbid conditions, the presence of cardiac arrhythmia, chronic renal failure, and CNS disorders was significantly higher in patients with dementia than in those without. However, none of these clinical conditions predicted in-hospital mortality in this group of patients. In this respect, our study extends prior research showing no direct relationship between mortality and the presence of comorbid conditions [19] and indicates dementia by itself as a terminal illness and main determinant of early death.

Furthermore, dementia is an independent risk factor for the development of multiple postoperative complications, particularly postoperative delirium (PD), which is also a major risk factor for postoperative mortality [2025]. Recently, Mosk et al. [25] observed PD in 34.2% of dementia patients following hip fracture surgery. In agreement with this, the current study found a significantly increased incidence of PD in patients with pre-existing dementia in comparison with those without. The increased incidence of PD (33%) in patients with pre-existing dementia is not surprising because in vulnerable patients, such as those with pre-existing dementia, even a seemingly minor insult such as minor surgery might be enough to precipitate delirium. Conversely, in younger patients without dementia, delirium may develop only after exposure to a series of noxious insults, such as general anesthesia, major surgery and a stay in the ICU [23]. In full agreement with this, in the current study, with only 3 out of 120 patients in the non-dementia group developing this complication, PD was an extremely rare occurrence in this group of patients.

In addition, the occurrence of postoperative delirium correlated strongly with urgent operations, longer intensive care unit stays and longer overall hospital stays (data not shown), emphasizing the need for early diagnosis and aggressive therapy. This agrees with previous research that found an overall longer hospital stay in dementia patients with delirium [26] and an association with an up to fourfold increase in mortality following surgery [2022, 24, 25, 27].

Hu et al. [14] found pneumonia to be one of the major complications that occurs frequently in surgical patients with pre-existing dementia compared with those patients without. This agrees with our result that showed a significantly higher incidence of postoperative pneumonia in dementia patients. The pneumonia rate among these patients was three times that among sex- and treatment-matched controls. The mortality rate after the development of pneumonia was substantially higher (41%) than the mortality rate for patients in whom such a complication had not developed after surgery. The inability of dementia patients to communicate reasonably and their related inability to participate fully in aggressive postoperative pulmonary exercises, toileting, and ambulation may explain the increased incidence of postoperative pneumonia. Interestingly, however, contrary to other studies that found COPD as a risk factor for pulmonary complications [28], postoperative pneumonia did not correlate with the presence of COPD as a coexisting disease in the present study. However, due to the relatively low prevalence of COPD in the studied patients, this notion may not reflect accurately the influence of pre-existing COPD on the incidence of postoperative pneumonia.

Surgical site infection, acute renal failure requiring dialysis and lung failure requiring intubation are also common postoperative complications, and survival was poor after the onset of these complications. Thus, the combined higher incidence of these adverse postoperative events could lead to a comparably increased risk of early death. Overall, however, although these complications may be heralds of early death, it is the pre-existing condition, in this case, dementia, that is the major problem and underlying cause of death.

Taken as a whole, while treating surgical patients with pre-existing dementia, surgeons should be aware of the limited life expectancy, poor prognosis and the expected severe and multiple complications. With the exception of emergency situations, the indication of burdensome surgical interventions of questionable benefit should be assessed critically, unless this step is necessary to reduce physical suffering. If available, a conservative treatment approach is a more viable option in this difficult to treat patient population.

Several limitations of this study deserve comment. First, we did not have detailed information on the severity of dementia. Thus, it is possible that some individuals with mild cognitive impairment may not have been identified. Accordingly, the presented results may not represent the outcomes of patients with mild dementia that has not yet been clinically recognized by a physician.

Second, specific surgical procedures in this study are heterogeneous. Included procedures that ranged from adhesiolysis to multi-visceral resection do not provide a uniform baseline surgical stress, which leads to variability in measurements such as operative time, requirement of a postoperative ICU stay and length of hospital stay. However, relatively similar types and numbers of operations were performed in patients with and without dementia.

Third, this study is limited in its ability to draw strong conclusions regarding the outcomes of surgery among patients with coexisting dementia compared to patients without. The descriptive analysis employed suggests differences among the groups for some patient and surgical variables including age.

Finally, we were limited also by the retrospective nature of our study and the short-term follow-up of our patient cohort.

Overall, however, the outcome of an institution-based cohort of patients with and without dementia diagnosed with general and vascular conditions that required surgery was described. We feel that our review of outcomes for 120 operated patients with a pre-existing diagnosis of dementia compared with the results of an equal number of sex- and treatment-matched controls with several well-balanced clinical variables accurately reflects surgical outcomes among this patient population.

Conclusions

Patients with pre-existing dementia have a greater than average risk of early death after surgery, and their incidence of fatal complications is higher than that of surgical patients without dementia. The predominant causes of in-hospital mortality after surgery are infectious and cardiac in nature. Patients at greatest risk of early death are those with a higher ASA class, who undergo emergent operations and develop postoperative pulmonary complications. Despite the inferior surgical outcomes and limited life expectancy, the lack of effective alternative therapy may justify a surgical approach for a surgical diagnosis in these difficult-to-treat patients. Further research is needed to develop strategies to optimize the surgical management of patients with dementia in order to address the challenges they present.

Abbreviations

ARF: 

Acute renal failure

ASA: 

The American Society of Anesthesiologists Physical Status classification

BMI: 

Body mass index

CA: 

Cardiac arrhythmia

CCI: 

Comprehensive complication index

CNS: 

Central nervous system disease

COD: 

Coexisting disease

COPD: 

Chronic obstructive lung disease

CRF: 

Chronic renal failure

DC: 

Clavien-Dindo classification of complications

GS: 

General surgery

ICD: 

International Statistical Classification of Diseases and Related Health Problems

ICU: 

Intensive care unit

LFRI: 

Lung failure requiring intubation

LOS: 

Length of hospital stay

PD: 

Postoperative delirium

PERI: 

Pleural effusion requiring intervention

SSI: 

Surgical site infection

TIA: 

Transitory ischemic attack

VS: 

Vascular surgery

Declarations

Acknowledgements

I would like to thank all colleagues at our institutions that provided and cared for patients and made this study possible.

Funding

I acknowledge support from the German Research Foundation (DFG) and Leipzig University within the program of Open Access Publishing. These funding bodies played no role in the design of the presented study and collection, analysis, and interpretation of data and in writing the manuscript.

Availability of data and materials

The datasets generated and/or analyzed during the current study are not publicly available due to internal institutional restrictions but are available from the corresponding author on reasonable request and with the permission of the institution where the data was generated.

Author’s contributions

Study conception, and design: WTK. Acquisition, analysis and interpretation of data: WTK. Drafting of manuscript: WTK. Critical revision: WTK. The author read and approved the final manuscript.

Ethics approval and consent to participate

This study was approved by the institutional ethic committee review board of the medical faculty of the University of Leipzig in Leipzig, Germany. Registration number: 347/17-ek. Formal written informed consent from participants or health care proxies was obtained during admission for surgery. Given the anonymous nature of the data, written informed consent from patients or health care proxies was not required to conduct this research.

Consent for publication

Not applicable

Competing interests

The author declares that he has no competing interests.

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Authors’ Affiliations

(1)
Clinic for Visceral, Transplantation, Thoracic and Vascular Surgery, University of Leipzig, Leipzig, Germany

References

  1. Gajdos C, Kile D, Hawn MT, Finlayson E, Henderson WG, Robinson TN. The significance of preoperative impaired sensorium on surgical outcomes in nonemergent general surgical operations. JAMA Surg. 2015;150:30–6.View ArticlePubMedGoogle Scholar
  2. Sosa-Ortiz AL, Acosta-Castillo I, Prince MJ. Epidemiology of dementias and Alzheimer's disease. Arch Med Res. 2012;43:600–8.View ArticlePubMedGoogle Scholar
  3. W H, Goodkind D, Kowal P. U.S. Census Bureau, International Population Reports, P95/16–1, An Aging World:2015, U.S. Washington: Government Publishing Office; 2016.Google Scholar
  4. Prince M, Bryce R, Albanesse E, Wimo A, Riberio W, Ferri CP. The global prevalence of dementia: a systematic review and metanalysis. Alzheimers Dement. 2013;9:63–75.e2.View ArticlePubMedGoogle Scholar
  5. Steunenberg SL, Te Slaa A, Ho GH, Veen EJ, de Groot HGW, van der Laan L. Dementia in patients suffering from critical limb ischemia. Ann Vasc Surg. 2017;38:268–73.View ArticlePubMedGoogle Scholar
  6. Bernstein GM, Offenbartl SK. Adverse surgical outcomes among patients with cognitive impairments. Am Surg. 1991;57:682–90.PubMedGoogle Scholar
  7. Seitz DP, Gill SS, Gruneir A, Austin PC, Anderson GM, Bell CM, et al. Effects of dementia on postoperative outcomes of older adults with hip fractures: a population-based study. J Am Med Dir Assoc. 2014;15:334–41.View ArticlePubMedGoogle Scholar
  8. Van Dijk PTM, Dippel DWS, Habbena JDF. Survival of patients with dementia. J Am Geriatr Soc. 1991;39:603–10.View ArticlePubMedGoogle Scholar
  9. Ientile L, De Pasquale R, Monacelli F, Odetti P, Traverso N, Cammarata S, et al. Survival rate in patients affected by dementia followed by memory clinics (UVA) in Italy. J Alzheimers Dis. 2013;36:303–9.View ArticlePubMedGoogle Scholar
  10. Kua EH, Ho E, Tan HH, Tsoi C, Thng C, Mahendran R. The natural history of dementia. Psychogeriatrics. 2014;14:196–201.View ArticlePubMedGoogle Scholar
  11. Graham R. Cognitive citizenship: access to hip surgery for people with dementia. Health (London). 2004;8:295–310.View ArticleGoogle Scholar
  12. Khan MA, Hossain FS, Ahmed I, Muthukumar N, Mohsen A. Predictors of early mortality after hip fracture surgery. Int Orthop. 2013;37:2119–24.View ArticlePubMedPubMed CentralGoogle Scholar
  13. Tsuda Y, Yasunaga H, Horiguchi H, Ogawa S, Kawano H, Tanaka S. Association between dementia and postoperative complications after hip fracture surgery in the elderly: analysis of 87,654 patients using a national administrative database. Arch Orthop Trauma Surg. 2015;135:1511–7.View ArticlePubMedGoogle Scholar
  14. Hu CJ, Liao CC, Chang CC, Wu CH, Chen TL. Postoperative adverse outcomes in surgical patients with dementia: a retrospective cohort study. World J Surg. 2012;36:2051–8.View ArticlePubMedGoogle Scholar
  15. Owens WD, Felts JA, Spitznagel EL Jr. ASA physical status classifications: a study of consistency of ratings. Anesthesiology. 1978;49:239–43.View ArticlePubMedGoogle Scholar
  16. Clavien PA, Barkun J, de Oliveira ML, Vauthey JN, Dindo D, Schulick RD, et al. The Clavien-Dindo classification of surgical complications: five-year experience. Ann Surg. 2009;250:187–96.View ArticlePubMedGoogle Scholar
  17. Clavien PA, Vetter D, Staiger RD, Slankamenac K, Mehra T, Graf R, et al. The comprehensive complication index (CCI®): added value and clinical perspectives 3 years "down the line". Ann Surg. 2017;265:1045–50.View ArticlePubMedGoogle Scholar
  18. Kassahun WT, Staab H, Gockel I, Mehdorn M. Factors associated with morbidity and in-hospital mortality after surgery beyond the age of 90: comparison with outcome results of younger patients matched for treatment. Am J Surg. 2017; https://doi.org/10.1016/j.amjsurg.2017.11.032.
  19. Mitchell SL, Teno JM, Kiely DK, Shaffer ML, Jones RN, Prigerson HG, et al. The clinical course of advanced dementia. N Engl J Med. 2009;361:1529–38.View ArticlePubMedPubMed CentralGoogle Scholar
  20. Edelstein DM, Aharonoff GB, Karp A, Capla EL, Zuckerman JD, Koval KJ. Effect of postoperative delirium on outcome after hip fracture. Clin Orthop Relat Res. 2004;422:195–200.View ArticleGoogle Scholar
  21. Baker NL, Cook MN, Arrighi HM, Bullock R. Hip fracture risk and subsequent mortality among Alzheimer's disease patients in the United Kingdom, 1988-2007. Age Ageing. 2011;40:49–54.View ArticlePubMedGoogle Scholar
  22. Robinson TN, Wu DS, Pointer LF, Dunn CL, Moss M. Preoperative cognitive dysfunction is related to adverse postoperative outcomes in the elderly. J Am Coll Surg. 2012;215:12–8.View ArticlePubMedPubMed CentralGoogle Scholar
  23. Inouye SK, Westendorp RG, Saczynski JS. Delirium in elderly people. Lancet. 2014;383:911–22.View ArticlePubMedGoogle Scholar
  24. Gleason LJ, Schmitt EM, Kosar CM, Tabloski P, Saczynski JS, Robinson T, et al. Effect of delirium and other major complications on outcomes after elective surgery in older adults. JAMA Surg. 2015;150:1134–40.View ArticlePubMedPubMed CentralGoogle Scholar
  25. Mosk CA, Mus M, Vroemen JP, van der Ploeg T, Vos DI, Elmans LH, et al. Dementia and delirium, the outcomes in elderly hip fracture patients. Clin Interv Aging. 2017;12:421–30.View ArticlePubMedPubMed CentralGoogle Scholar
  26. Fick DM, Steis MR, Waller JL, Inouye SK. Delirium superimposed on dementia is associated with prolonged length of stay and poor outcomes in hospitalized older adults. J Hosp Med. 2013;8:500–5.View ArticlePubMedPubMed CentralGoogle Scholar
  27. Bellelli G, Mazzola P, Morandi A, Bruni A, Carnevali L, Corsi M, et al. Duration of postoperative delirium is an independent predictor of 6-month mortality in older adults after hip fracture. J Am Geriatr Soc. 2014;62:1335–40.View ArticlePubMedGoogle Scholar
  28. Rock P, Rich PB. Postoperative pulmonary complications. Curr Opin Anaesthesiol. 2003;16:123–31.View ArticlePubMedGoogle Scholar

Copyright

© The Author(s). 2018

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