Table 3.

Prevalence rate ratio of lower-extremity amputation in relation to demographic and geographic factors

	Model 1	Model 2
	Prevalence rate ratio (95% CI)	Prevalence rate ratio (95% CI)
Year
2009	Ref.	Ref.
2010	0.91 (0.85–0.97)**	0.90 (0.85–0.96)**
2011	0.80 (0.75–0.85)**	0.80 (0.75–0.86)**
2012	0.65 (0.60–0.69)**	0.65 (0.61–0.70)**
2013	0.68 (0.63–0.72)**	0.68 (0.63–0.72)**
P-value for trend	< 0.001	< 0.001
Sex
Female	Ref.	Ref.
Male	1.46 (1.40–1.52)**	1.46 (1.40–1.52)**
Age (years)
55–64	Ref.	Ref.
65–74	1.12 (1.07–1.18)**	1.12 (1.07–1.19)**
75–84	1.38 (1.30–1.45)**	1.38 (1.31–1.46)**
85 and over	1.76 (1.63–1.9)**	1.12 (1.07–1.19)**
P-value for trend	< 0.001	< 0.001
Comorbidities
Hypertension	1.78 (1.69–1.88)**	1.78 (1.69–1.88)**
Nephropathy	2.51 (2.33–2.70)**	2.50 (2.33–2.69)**
CVD	2.29 (2.2–2.39)**	2.29 (2.19–2.39)**
Urbanization
Urban	Ref.	Ref.
Sub-urban	1.47 (1.40–1.54)**	1.47 (1.39–1.55)**
Rural	1.68 (1.58–1.78)**	1.68 (1.56–1.82)**
P-value for trend	< 0.001	< 0.001
Median family income (NTD)
585,000 and over		Ref.
533,000-584,999		1.08 (1.02–1.14)**
501,000-532,999		1.03 (0.95–1.10)
0–501,000		1.05 (0.97–1.13)
P-value for trend		0.434
Density of surgeons (no. per 105 population)
20 and over		Ref.
10–19		0.94 (0.87–1.02)
5–9		0.96 (0.87–1.07)
0–4		1.01 (0.91–1.13)
P-value for trend		0.544
Density of internal medicine (no. per 105 population)
40 and over		Ref.
20–39		0.98 (0.90–1.06)
10–19		1.01 (0.90–1.12)
0–9		0.94 (0.85–1.06)
P-value for trend		0.240
Density of family medicine (no. per 105 population)
20 and over		Ref.
15–19		0.95 (0.89–1.03)
10–14		0.92 (0.86–1.00)**
0–9		0.98 (0.91–1.06)
P-value for trend		0.917

** P < 0.05

NTD New Taiwan Dollar (1 USD ≈ 32 NTD)

CVD cerebral vascular disease