Risk factors for hospital readmission in older adults within 30 days of discharge – a comparative retrospective study

Table 3 Variables related to the initial hospitalisation and discharge

Variable	Comparison group (n = 360)	Readmitted < 30 days (n = 360)	p-value
Emergent hospitalisation, %	88	93	0.058^c
Hospitalisation related to cancer diagnosis, %	6.9	11	0.051^c
Length of stay, Mean (SD)	6.9 (7.2)	7.8 (5.2)	0.063^b
Length of stay 5 days or longer, %	53	66	< 0.001^c
*Laboratory and test results (last result before discharge)*
Plasma sodium level, mmol/L, Mean (SD)	140 (3.7)	139 (3.8)	0.267^{b, e}
Plasma potassium level, mmol/L, Mean (SD)	4.0 (0.4)	4.0 (0.4)	0.815^{b, e}
Blood haemoglobin level, g/L, Mean (SD)	124 (19.2)	119 (18.1)	< 0.001^{b, e}
Relative eGFR^a, Mean (SD)	59 (18.2)	55 (20.9)	0.006^{b, d}
Body Mass Index < 22, kg/m², %	30	35	0.153^{c, f}
*Procedure performed during hospital stay*
Minor surgery/diagnostic procedure, %	33	37	0.241^c
Major surgery, %	31	21	0.002^c
*Variables concerning discharge*
Discharged Monday-Thursday, %	70	66	0.230^{c, d}
Discharged Friday or day before holiday, %	19	27	0.012^{c, d}
Discharged weekend or holiday, %	11	6.7	0.064^{c, d}
Discharged from Internal medicine, %	56	54	0.600^c
Discharged from General surgery, %	21	28	0.046^c
Discharged from Infection, %	7.2	6.1	0.550^c
Discharged from Orthopaedics, %	11	8.9	0.320^c
Discharged from Gynaecology/ENT unit, %	4.2	3.3	0.556^c

Abbreviations: ENT Ear Nose Throat, eGFR Estimated Glomerular Filtration Rate, SD Standard Deviation
^aVariables included in the Charlson Comorbidity Index ^bStudent’s t-test ^cχ²-test ^dInternal missing 0.4–1.7% ^eInternal missing 3.2–4.6% ^fInternal missing 13.5%
Significant p-values are indicated in bold.

ISSN: 1471-2318