Table 3.

Unadjusted and adjusted RRs of total CDI incidence compared with total antibiotic prescribing

	Unadjusted	Adjusted
	RR (95% CI)	RR (95% CI)	P value
Total antibiotics (per 1000 items per 1000 STAR-PU)	1.3375 (1.1696–1.5293)	1.1413 (0.9714–1.3404)	0.108
Financial year
2014–15	1	1	—
2015–16	0.9453 (0.8518–1.0490)	0.9397 (0.8518–1.0365)	0.214
2016–17	0.7901 (0.7095–0.8798)	0.7823 (0.7056–0.8672)	<0.001
2017–18	0.8388 (0.7541–0.9330)	0.8257 (0.7455–0.9144)	<0.001
Health boards (1–7)	—	—	<0.001
Patients aged ≥65 years (per 1% increase)	1.0370 (1.0293–1.0447)	1.0269 (1.0134–1.0407)	0.001
Social deprivation score (per 1% increase)	0.9995 (0.9980–1.0009)	1.0002 (0.9980–1.0025)	0.856
PPI (per 1000 items per 1000 patients)	1.0175 (1.0105–1.0246)	0.9967 (0.9877–1.3404)	0.481
COPD (per 1% increase)	1.1732 (1.1196–1.2292)	1.0594 (0.9906–1.1322)	0.093
Diabetes (per 1% increase)	1.1518 (1.1138–1.1913)	1.0609 (1.0023–1.1227)	0.039
Hypertension (per 1% increase)	1.0550 (1.0426–1.0676)	1.0051 (0.9841–1.0264)	0.639

Unadjusted models include only one predictor variable (univariate analysis). Adjusted models are adjusted for financial year, health board, percentage of patients aged ≥65 years, social deprivation score (percentage of registered patients living in the most deprived areas), PPI (per 1000 items per 1000 registered patients) and percentage of patients with COPD, diabetes and hypertension.