Application of survival tree analysis for exploration of potential interactions between predictors of incident chronic kidney disease: a 15-year follow-up study

Table 5 Multivariate Cox regression analysis of factors associated with CKD incidence in total population, Tehran Lipid and Glucose Study (1999–2014)

Variables	HR	95% CI	p-value
Gender
Male	Reference
Female	2.09	1.82–2.39	< 0.001
Age (years)	1.03	1.02–1.03	< 0.001
eGFR (ml/min/1.73 m²)	0.91	0.90–0.92	< 0.001
Waist circumference (cm)	0.99	0.98–0.99	< 0.001
FPG (mmol/l)	1.06	1.03–1.09	< 0.001
Heart rate (beats/min)	0.99	0.98–0.99	< 0.001
TC (mmol/l)	0.95	0.91–0.99	0.043
DBP (mmHg)	1.01	1.00–1.01	0.045
SBP (mmHg)	1.00	0.99–1.00	0.056
Wrist circumference (cm)	1.05	0.99–1.10	0.077
Education
Level 1 (illiterate)	Reference
Level 2 (< 9 years)	1.05	0.89–1.24	0.541
Level 3 (9–12 years)	1.11	0.92–1.33	0.255
Level 4 (> 12 years)	1.41	1.14–1.72	0.001
Marital status
Married	Reference
Single	0.90	0.74–1.09	0.312
Divorced/widowed	1.19	0.99–1.42	0.057
FHD in first-degree relatives
No	Reference
Yes	0.90	0.82–0.99	0.045
Use of blood glucose lowering drugs
No	Reference
Yes	1.22	0.96–1.56	0.097
PAL
Inactive^a	Reference
Active	1.09	0.99–1.20	0.064
Prevalence CVD
No	Reference
Yes	1.25	1.01–1.54	0.035

The Stepwise Cox PH regression model using AIC as model selection approach was used to identify significant predictors of incident CKD by calculating multivariable hazard ratios (HRs) with 95% CI
TLGS Tehran Lipid and Glucose Study, PH proportional hazard, CI confidence interval, AIC Akaike information criteria, FPG fasting plasma glucose, TC total cholesterol, eGFR estimated glomerular filtration rate, SBP systolic blood pressure, DBP diastolic blood pressure, FHD family history of diabetes mellitus, PAL physical activity level, CVD cardiovascular disease
^aDoing exercise or labor less than three times a week or performing activities achieving < 600 metabolic equivalent of task (MET)

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