Table 3.

Cox proportional hazard regression for estimation of adjusted hazard ratios on fibromyalgia.

	aHR (95% CI)
	Age–sex matched population		PSM population
Variable	Univariate	Multiple	Conditional cox
AS	1.60 (1.37–1.85)	1.28 (1.09–1.50)	1.39 (1.16–1.67)
Sex of male	0.75 (0.66–0.86)	0.93 (0.81–1.07)
Age
<30	0.62 (0.50–0.78)	0.65 (0.52–0.81)
30–45	Reference	Reference
45–65	1.46 (1.22–1.74)	1.34 (1.12–1.61)
≥65	2.24 (1.85–2.70)	1.89 (1.53–2.34)
Urbanization
Urban	Reference	Reference
Sub-urban	1.17 (1.00–1.36)	1.11 (0.95–1.29)
Rural	1.89 (1.55–2.29)	1.64 (1.35–2.00)
Length of hospital stays†, day
0	Reference	Reference
1–6	1.24 (0.94–1.65)	0.94 (0.70–1.25)
≥7	1.33 (0.94–1.89)	0.82 (0.57–1.17)
Co-morbidity†
RA	1.01 (0.57–1.79)	0.67 (0.38–1.19)
Hypertension	1.82 (1.55–2.14)	0.91 (0.75–1.11)
Diabetes mellitus	2.04 (1.66–2.52)	1.28 (1.01–1.62)
Hyperlipidemia	1.89 (1.54–2.32)	1.07 (0.85–1.35)
CKD	1.81 (0.94–3.48)	1.03 (0.53–2.01)
COPD	1.40 (1.07–1.82)	0.91 (0.69–1.19)
Chronic liver diseases	1.61 (1.25–2.07)	1.13 (0.88–1.47)
Gout	2.03 (1.60–2.57)	1.45 (1.13–1.86)
Depression	2.48 (2.07–2.98)	1.80 (1.49–2.18)
Use of NSIADs†	2.07 (1.75–2.46)	1.70 (1.42–2.04)

^†The length of hospital stays, co-morbidity, use of medication were identified within 1 year before index date.