Results
Characteristics of individuals with and without dialysis in the presence or absence of DM are shown in Table 1. The medium follow-up period was 5.2 years. During the follow-up, 113 individuals (0.047%) in the without DM group ( DM-) and 76 individuals (0.44%) in the with DM group ( DM+) developed the need for dialysis. The incidence of dialysis was 0.079 per 1000 person-years in the DM- group and 0.672 per 1000 person-years in the DM+ group. As shown in Table 1, among DM- , baseline age, percent of men, body mass index (BMI), smoking rate, SBP, DBP, percent of users of medication for hypertension, and prevalence of coronary artery disease were significantly higher in individuals with dialysis compared with those without dialysis. High-density lipoprotein cholesterol (HDL-C) was significantly lower in individuals with dialysis than without dialysis. Among DM+,baseline percentage of men, SBP, HbA1c, percentages of users of medication for DM and hypertension, and prevalence of coronary artery disease were significantly higher in individuals with dialysis compared with those without dialysis. HDL-C was significantly lower in individuals with dialysis than in those without dialysis.
Table 2 shows Cox proportional hazard models for various risk factors for the initiation of dialysis in participants with and without DM. Each stratified SBP level includes the specified cutoff value and upward (for example, SBP ≥110 mmHg and upward). SBP ≥140 mmHg was an independent predictor for the initiation of dialysis in the DM- group whereas SBP ≥150 mmHg was an independent predictor in the DM+ group.
Figure 1 shows the cumulative incidence of the initiation of dialysis according to five stratified SBP values (i.e., ≤119 mmHg, 120-129 mmHg, 130-139 mmHg, 140-149 mmHg, ≥150 mmHg) and the presence or absence of DM. Hypertension was an independent predictor of the initiation of dialysis, and the incidence of starting dialysis in the DM+ group with SBP ≤119 mmHg was almost the same as in the DM- group with SBP ≥150 mmHg.
Table 3 shows Cox proportional hazard models for ten groups divided according to combinations of DM+ and DM- and five stratified levels of systolic SBP (i.e., ≤119 mmHg, 120-129 mmHg, 130-139 mmHg, 140-149 mmHg, ≥150 mmHg) for the initiation of dialysis. HRs for the initiation of dialysis among DM- and SBP ≥150 mmHg and DM+ and SBP ≥150 mmHg were 2.87 (1.55-5.32) and 2.28 (1.03-5.01), respectively, values that were quite similar. Compared with DM- and SBP ≤119 mmHg, HRs for the initiation of dialysis among DM- and SBP ≥150 mmHg, and DM+ and SBP ≤119 mmHg were about 3 times greater. Compared with DM- and SBP ≤119 mmHg, the HR for the initiation of dialysis in DM+ and SBP ≥150 mmHg was 6.88 (3.66-12.9). No interaction was observed according to SBP levels and DM status.