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Table 5 Polypharmacy, PIMs and DDIs and associated factors (bold numbers = significant results)

From: Epidemiology and associated factors of polypharmacy in older patients in primary care: a northern Italian cross-sectional study

Polypharmacy in relation to GPs’ and patients’ characteristics
Comparison of median values Number of drugs p-value
Patient’s sex Male Female  
Median (IQR) 9 (8 – 10) 9 (8 – 11) 0.319 a
GP’s sex Male Female  
Median (IQR) 9 (8 – 10) 9 (8 – 11) 0.818 a
Rural / urban area Rural Urban  
Median (IQR) 9 (8 – 10) 9 (8 – 10) 0.655 a
Correlation analysis Correlation coefficient p-value
n drugs – patient’s age 0.06 0.146 b
n drugs – n chronic conditions 0.20 < 0.001 b
n drugs – BMI 0.01 0.817 b
n drugs – 6-CIT score 0.03 0.524 b
n drugs – 5-GDS score (unadjusted) 0.12 0.003 b
n drugs – 5-GDS score (adjusted)c 0.10 0.017 c
n drugs – EQ-5D index value (unadjusted) - 0.14 0.001 b
n drugs – EQ-5D index value (adjusted)c - 0.09 0.034 c
n drugs – EQ-VAS score (unadjusted) - 0.14 0.001 b
n drugs – EQ-VAS score (adjusted)c - 0.11 0.006 c
Logistic regression analysis of hyperpolypharmacy
(use of ≥10 drugs)
Crude analysis Adjusted analysis (by age, sex, n conditions, 6-CIT)
OR p-value OR p-value
Hyperpolyharmacy – n chronic conditions 1.26 < 0.001 1.23 < 0.001
Hyperpolyharmacy – 6-CIT score 1.01 0.692 0.99 0.583
Hyperpolyharmacy – EQ-5D index value 0.85 < 0.001 0.87 0.008
Hyperpolyharmacy – EQ-VAS score 0.86 0.007 0.89 0.035
Hyperpolyharmacy – 5-GDS score 1.19 0.021 1.16 0.065
PIM use (Beers-listed drugs) in relation to patient’scharacteristics
   p-value
Patient’s sex Male Female  
% of patients with 0 Beers-listed drug 51.7% 55.6% 0.385d
% of patients with 1 Beers-listed drug 36.1% 35.5%  
% of patients with ≥2 Beers-listed drugs 12.2% 8.9%  
Correlation analysis Correlation coefficient p-value
n Beers-listed drugs – patient’s age 0.04 0.358 b
n Beers-listed drugs – n chronic conditions 0.05 0.252 b
n Beers-listed drugs – n drugs (unadjusted) 0.07 0.089 b
n Beers-listed drugs – n drugs (adjusted)c 0.06 0.156 c
DDIs in relation to patient’s characteristics
   p-value
Patient’s sex Male Female  
% of patients with 0 D/X drug-drug interactions 30.4% 33.8%  0.374d
% of patients with 1 D/X drug-drug interactions 35.7% 30.1%  
% of patients with ≥2 D/X drug-drug interactions 33.9% 36.1%  
Correlation analysis Correlation coefficient p-value
n D/X-DDIs – patient’s age 0.04 0.348 b
n D/X-DDIs – n chronic conditions 0.05 0.220 b
n D/X-DDIs – n drugs (unadjusted) 0.33 < 0.001 b
n D/X-DDIs – n drugs (adjusted) c 0.33 < 0.001 c
  1. PIM Potentially inappropriate medication, DDIs Drug-drug interactions, GP General practitioner, IQR Interquartile range, BMI Body mass index, 6-CIT 6-Item Cognitive Impairment Test, 5-GDS 5-Item Geriatric Depression Scale, EQ-5D 5-Item questionnaire measuring health-related quality of life, VAS Visual analogue scale, OR Odds Ratio
  2. a Wilcoxon rank-sum test
  3. b Spearman correlation unadjusted (crude)
  4. c Spearman correlation adjusted by age, sex, number of chronic conditions, cognitive function (6-CIT)
  5. d Fisher’s exact test