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

Table 4 Multivariate Cox regression analysis of factors associated with CKD incidence by gender, Tehran Lipid and Glucose Study (1999–2014)

Variables	HRs	95% Confidence interval	p-value
Men
Age (years)	1.04	1.03–1.05	< 0.001
eGFR (ml/min/1.73 m²)	0.90	0.89–0.91	< 0.001
FPG (mmol/l)	1.10	1.05–1.16	< 0.001
DBP (mmHg)	1.02	1.01–1.03	< 0.001
TC (mmol/l)	0.89	0.83–0.96	0.0025
Waist circumference (cm)	0.98	0.97–0.99	0.016
Hip circumference (cm)	1.02	1.00–1.03	0.075
Heart rate (beats/min)	0.99	0.99–1.00	0.093
Education
Level 1 (illiterate)	Reference
Level 2 (< 9 years)	1.18	0.83–1.67	0.34
Level 3 (9–12 years)	1.24	0.87–1.78	0.23
Level 4 (> 12 years)	1.56	1.06–2.28	0.021
Marital status
Married	Reference
Single	1.06	0.77–1.47	0.70
Divorced/widowed	2.04	1.09–3.84	0.025
FH–CVD in female relatives
No	Reference
Yes	1.25	0.97–1.62	0.080
PAL
Inactive^a	Reference
Active	1.21	1.03–1.42	0.016
Smoking
Never	Reference
Past	1.06	0.87–1.30	0.51
Current	1.24	1.03–1.48	0.017
Use of blood glucose lowering drugs
No	Reference
Yes	1.59	1.08–2.35	0.017
Use of aspirin
No	Reference
Yes	0.84	0.67–1.04	0.116
Women
Age (years)	1.02	1.02–1.03	< 0.001
eGFR (mL/min/10.73 m²)	0.91	0.91–0.92	< 0.001
FPG (mmol/L)	1.05	1.02–1.08	< 0.001
Heart rate (beats/min)	0.99	0.98–0.99	< 0.001
Waist circumference (cm)	0.99	0.98–0.99	0.002
SBP (mmHg)	1.01	1.00–1.01	0.028
Wrist circumference (cm)	1.05	1.00–1.01	0.119
FHD in first-degree relatives
No	Reference
Yes	0.90	0.79–1.01	0.08
Prevalence CVD
No	Reference
Yes	1.35	0.99–1.82	0.048

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, AIC Akaike information criteria, TLGS Tehran Lipid and Glucose Study, FPG fasting plasma glucose, TC total cholesterol, eGFR estimated glomerular filtration rate, SBP systolic blood pressure, DBP diastolic blood pressure, FH-CVD family history of premature cardiovascular disease, 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)

ISSN: 1479-5876