Table 2.

Logistic and negative binomial regression analyses for PIP

Covariate	Adjusted logistic regression		Negative binomial regression

	OR (95% CI)	P-value	IRR (95% CI)	P-value
Year of study
2014 (reference)	1	—	1	—
2015	0.99 (0.97 to 1.02)	0.600	0.99 (0.97 to 1.01)	0.256
2016	0.95 (0.93 to 0.98)	0.001	0.95 (0.93 to 0.97)	<0.001
2017	0.90 (0.88 to 0.93)	<0.001	0.91 (0.89 to 0.93)	<0.001
2018	0.83 (0.80 to 0.86)	<0.001	0.83 (0.81 to 0.85)	<0.001
2019	0.81 (0.79 to 0.84)	<0.001	0.82 (0.80 to 0.84)	<0.001

Polypharmacy	4.85 (4.69 to 5.02)	<0.001	3.91 (3.80 to 4.03)	<0.001

Multimorbidity	2.61 (2.52 to 2.71)	<0.001	2.47 (2.38 to 2.55)	<0.001

Female sex	1.01 (0.97 to 1.04)	0.651	1.03 (1.01 to 1.06)	0.016

Age group
45–49 (reference)	1	—	1	—
50–54	1.05 (1.01 to 1.08)	0.017	1.03 (0.99 to 1.06)	0.111
55–59	1.10 (1.05 to 1.14)	<0.001	1.06 (1.02 to 1.09)	0.002
60–64	1.19 (1.14 to 1.25)	<0.001	1.11 (1.07 to 1.15)	<0.001

Deprivation quintile
5 (reference, least deprived)	1	—	1	—
4	1.09 (1.03 to 1.15)	0.002	1.09 (1.04 to 1.14)	<0.001
3	1.14 (1.08 to 1.20)	<0.001	1.12 (1.07 to 1.17)	<0.001
2	1.18 (1.12 to 1.25)	<0.001	1.17 (1.12 to 1.23)	<0.001
1 (most deprived)	1.17 (1.11 to 1.23)	<0.001	1.16 (1.11 to 1.21)	<0.001