Table 2.

The incidence rate and hazard ratios of NMSC and melanoma in HCTZ users versus non-HCTZ users

Variable	Event of skin cancer	Follow-up, PY	The incidence of 100,000 PY (95% CI)	Adjusted HR (95% CI)a	p value	Fully-adjusted HR (95% CI)b	p value
NMSC
Non-HCTZ users (n = 1,851,362)	2,811	8,355,577.42	33.64 (32.41–34.91)	1 (Ref)		1 (Ref)
HCTZ users (n = 1,327,256)	2,115	7,541,132.52	28.04 (26.86–29.27)	0.72 (0.68–0.77)	< 0.001c	0.96 (0.91–1.02)	0.236
Cumulative doses of HCTZ, mg
Non-user	2,811	8,355,577.42	33.64 (32.41–34.91)	1 (Ref)		1 (Ref)
Low user (< 50,000)	2,106	7,429,752.40	28.35 (27.15–29.58)	0.73 (0.69–0.77)	< 0.001c	0.97 (0.92–1.04)	0.499
High user (≥ 50,000)	9	111,380.13	8.08 (3.69–15.34)	0.20 (0.10–0.38)	< 0.001c	0.22 (0.11–0.42)	< 0.001c
Melanoma
Non-HCTZ users (n = 1,851,362)	706	8,360,968.10	8.44 (7.83–9.09)	1 (Ref)		1 (Ref)
HCTZ users (n = 1,327,673)	460	7,547,814.32	6.09 (5.55–6.68)	0.63 (0.56–0.71)	< 0.001c	0.85 (0.75–0.97)	0.016c
Cumulative doses of HCTZ, mg
Non-user	706	8,360,968.10	8.44 (7.83–9.09)	1 (Ref)		1 (Ref)
Low user (< 50,000)	458	7,436,256.36	6.16 (5.61–6.75)	0.64 (0.57–0.72)	< 0.001c	0.87 (0.77–0.99)c	0.031c
High user (≥ 50,000)	2	111,557.96	1.79 (0.22–6.48)	0.18 (0.04–0.70)	0.014c	0.20 (0.05–0.79)c	0.022c

NMSC, non-melanoma skin cancer; HCTZ, hydrochlorothiazide; PY, person-year; CI, confidence interval; HR, hazard ratio.

^aAdjusted for age, sex, and Charlson comorbidity index scores (0, low; 1 to 2, medium; ≥ 3, high).

^bAdjusted for age, sex, Charlson comorbidity index scores (0, low; 1 to 2, medium; ≥ 3, high), concurrent use of photosensitizing drugs, and concurrent use of drugs potentially affecting skin cancer.

^cp < 0.05 for HCTZ-users versus non-HCTZ users.