. Author manuscript; available in PMC: 2019 Aug 1.

Published in final edited form as: Drugs Aging. 2018 Aug;35(8):735–750. doi: 10.1007/s40266-018-0563-1

Table 4.

Incidence rate ratios and hazard ratios for hospitalization and death, respectively, by polypharmacy and PIM use

	Hospitalizations (N=4,178)^a among 2,197 participants				Death (N=344) among full cohort

Overall incidence rate	26 per 100 PYs				2 per 100 PYs

	Hospitalizations	Incidence rate	Unadjusted IRR	Adjusted IRR	Deaths	Incidence rate	Unadjusted HR	Adjusted HR

Polypharmacy (overall)
0–3 medications	607	15 per 100 PYs	0.85 (0.73–0.99)^*	0.91 (0.78–1.06)	53	1 per 100 PYs	1.07 (0.72–1.58)	1.17 (0.78–1.76)
4–5 medications	702	18 per 100 PYs	ref	ref	48	1 per 100 PYs	ref	ref
6–9 medications	1,664	29 per 100 PYs	1.67 (1.46–1.91)^*	1.37 (1.20–1.55)^*	141	3 per 100 PYs	1.99 (1.44–2.77)^*	1.65 (1.16–2.35)^*
10+ medications	1,205	49 per 100 PYs	2.88 (2.48–3.34)^*	1.93 (1.64–2.27)^*	102	4 per 100 PYs	3.42 (2.43–4.82)^*	2.40 (1.60–3.59)^*
Polypharmacy by CKD status^b
*CKD*
0–3 medications	188	25 per 100 PYs	1.10 (0.80–1.50)	1.13 (0.84–1.52)	20	3 per 100 PYs	1.37 (0.71–2.62)	1.57 (0.81–3.03)
4–5 medications	214	23 per 100 PYs	ref	ref	17	2 per 100 PYs	ref	ref
6–9 medications	705	39 per 100 PYs	1.76 (1.37–2.27)^*	1.45 (1.14–1.84)^*	73	4 per 100 PYs	2.19 (1.29–3.69)^*	1.91 (1.11–3.28)^*
10+ medications	558	57 per 100 PYs	2.60 (1.98–3.40)^*	1.85 (1.38–2.48)^*	55	6 per 100 PYs	3.12 (1.81–5.37)^*	2.58 (1.45–4.60)^*
*No CKD*	419	13 per 100	0.80	0.85	33	1 per 100	0.99	1.01
0–3 medications		PYs	(0.67–0.95)^*	(0.71–1.01)		PYs	(0.61–1.61)	(0.61–1.68)
4–5 medications	488	16 per 100 PYs	ref	ref	31	1 per 100 PYs	ref	ref
6–9 medications	959	25 per 100 PYs	1.53 (1.31–1.79)^*	1.33 (1.14–1.55)^*	68	2 per 100 PYs	1.66 (1.09–2.55)^*	1.51 (0.95–2.38)
10+ medications	647	44 per 100 PYs	2.81 (2.35–3.38)^*	2.01 (1.68–2.41)^*	47	3 per 100 PYs	3.09 (1.97–4.87)^*	2.40 (1.43–4.05)^*
PIM use
*Age-based PIM*
No	2,663	24 per 100 PYs	ref	ref	223	2 per 100 PYs	ref	ref
Yes	1,515	30 per 100 PYs	1.28 (1.15–1.43)^*	0.98 (0.88–1.09)	121	2 per 100 PYs	1.23 (0.99–1.54)	1.13 (0.88–1.46)
*Kidney-based PIM*^c
No	1,576	37 per 100 PYs	ref	ref	162	4 per 100 PYs	ref	ref
Yes	791	49 per 100 PYs	1.46 (1.17–1.81)^*	1.15 (0.91–1.45)	80	5 per 100 PYs	1.19 (0.78–1.80)	0.97 (0.59–1.58)
*Age- or kidney-based PIM*^c
No	1,291	38 per 100 PYs	ref	ref	137	4 per 100 PYs	ref	ref
Yes	1,076	43 per 100 PYs	1.32 (1.11–1.56)^*	1.05 (0.89–1.24)	105	4 per 100 PYs	1.26 (0.93–1.72)	1.28 (0.91–1.79)

Some participants had multiple hospitalizations during follow-up

Polypharmacy (categorical) and CKD status interaction not statistically significant

Includes participants with CKD only (eGFR <60 mL/min/1.73 m²)

=p≤0.05

Key: Potentially inappropriate medication (PIM); Chronic kidney disease (CKD); Incidence rate ratio (IRR); Hazard ratio (HR); Person years (PYs); estimated glomerular filtration rate (eGFR); Model was adjusted for estimated glomerular filtration rate, hypertension, cardiovascular disease, diabetes, heart failure, self-reported myocardial infarction, Charlson Comorbidity Index, frailty, sex, age, race, Body Mass Index, current smoking status, current alcohol use, Mini-Mental State Evaluation, high-density lipoproteins, low-density lipoproteins, triglycerides, and total vitamins/supplements. PIM use analyses were additionally adjusted by total number of medications (continuous)