Table 3. Influence of smoking dose on the risk of a 30% decline in eGFR.

	Univariate model		Multivariate model
	HR (95% CI)	P value	HR (95% CI)	P value
Model 1
No. of cigarettes (/10/d)	1.32 (1.05–1.63)	0.021	1.61 (1.23–2.09)	<0.001
Model 2
1–20 pack-years	1.07 (0.17–3.75)	0.933	1.36 (0.20–5.94)	0.715
21–39 pack-years	1.64 (0.47–4.49)	0.399	3.51 (0.87–12.5)	0.076
≥40 pack-years	2.61 (1.21–5.48)	0.016	5.56 (2.17–14.6)	<0.001
Test for trend		0.015		<0.001

HR, hazard ratio; CI, confidence interval.

Data are the HR, 95% CI, and P value from Cox proportional hazard regression analyses.

“Never smoked” was used as the reference category. Models 1 and 2 are based on data from 168 patients because the number of cigarettes was missing for 1 current and 2 ex-smokers. Adjusted for baseline characteristics (age, sex, systolic/diastolic pressure, serum creatinine level, urinary protein, use of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker within 6 months after kidney biopsy, and immunosuppressive therapy within 6 months after kidney biopsy).