Baseline features and results of follow-up including follow-up rate, data at follow-up, number of cases who developed ESRD and are deceased, and incidence density of ESRD and death in Japanese patients with T1DM according to the year of T1DM diagnosis
| Overall | Year of T1DM diagnosis | |||
|---|---|---|---|---|
| (N=1014) | (A) 1961–1984 (N=529) | (B) 1985–1999 (N=485) | p Value | |
| Male (%) | 372 (36.7) | 201 (38.0) | 171 (35.3) | NS |
| Age at baseline (years) | 19.7±8.4 | 19.3±9.3 | 20.0±7.3 | NS |
| Age at diagnosis (years) | 14.6±7.7 | 11.8±7.1 | 17.6±7.1 | <0.0001 |
| Calendar year of baseline <1980, N (%) | 162 (16.0) | 162 (30.6) | ||
| 1980–1989, N (%) | 312 (30.8) | 214 (40.5) | 98 (20.2) | <0.0001 |
| 1990–1999, N (%) | 540 (53.3) | 153 (28.9) | 387 (79.8) | |
| Duration of diabetes at baseline (years) | 5.1±6.1 | 7.5±7.1 | 2.4±3.1 | <0.0001 |
| Proteinuria at baseline, N (%) | 48/977 (4.9) | 44/507 (8.7) | 4/470 (0.9) | <0.0001 |
| Retinopathy at baseline, N (%) | 218/961 (22.7) | 184/499 (36.9) | 34/462 (7.4) | <0.0001 |
| HbA1c at baseline (%, mmol/mol)* | 10.4±2.8 (90±24) | 10.6±2.6 (92±23) | 10.2±2.9 (91±23) | NS |
| Systolic BP at baseline (mm Hg) | 112.8±14.9 | 115.5±15.5 | 109.9±13.6 | <0.0001 |
| RASI use at baseline, N (%) | 3/1006 (0.3) | 3/518 (0.6) | 0/488 (0.0) | NS |
| Statin use at baseline, N (%) | 2/1008 (0.2) | 1/518 (0.2) | 1/490 (0.2) | NS |
| Status confirmed for ESRD and death (N, %) | 895 (88.3) | 471 (89.0) | 424 (87.4) | NS |
| Year of follow-up (years) | 19.3±9.0 | 22.7±10.1 | 15.6±5.6 | <0.0001 |
| Age at the end of follow-up (years) | 38.9±9.6 | 42.0±9.6 | 35.6±8.5 | <0.0001 |
| Mean values of HbA1c during the follow-up (%, mmol/mol)) | 8.6±1.4 (70±12) | 8.8±1.4 (73±12) | 8.4±1.4 (68±12) | <0.0001 |
| Mean values of systolic BP during follow-up (mm Hg) | 121.4±10.5 | 123.0±10.9 | 119.7±9.8 | <0.0001 |
| RASI use at follow-up, N (%) | 187/984 (19.0) | 126/508 (24.8) | 61/476 (12.8) | <0.0001 |
| Statin use at follow-up, N (%) | 108/985 (11.0) | 71/510 (13.9) | 37/475 (7.8) | <0.01 |
| Current smoker at follow-up, N (%) | 189/804 (23.5) | 109/465 (23.2) | 81/339 (23.9) | NS |
| ESRD (N, %) | 66 (6.5) | 60 (11.3) | 6 (1.2) | <0.0001 |
| Person-years of follow-up for ESRD | 19 531 | 11 986 | 7545 | |
| Incidence of ESRD (95% CI, /1000 person-years) | 3.4 (2.6 to 4.3) | 5.0 (3.8 to 6.4) | 0.8 (0.3 to 1.7) | |
| RR (95% CI) | 1.0 | 0.16 (0.06 to 0.37) | <0.0001 | |
| All-cause death (N, %) | 72 (7.1) | 56 (10.6) | 16 (3.3) | <0.0001 |
| Person-years of follow-up for death | 21 617 | 13 410 | 8207 | |
| Incidence of all-cause death (95% CI, /1000 person-years) | 3.3 (2.6 to 4.2) | 4.2 (3.2 to 5.4) | 1.9 (1.1 to 3.2) | |
| RR (95% CI) | 1.0 | 0.47 (0.25 to 0.83) | <0.01 | |
| Death without ESRD (N, %) | 52 (5.1) | 37 (7.0) | 15 (3.1) | <0.01 |
| Person-years of follow-up for death without ESRD | 20 968 | 12 796 | 8172 | |
| Incidence of death without ESRD (95% CI, /1000 person-years) | 2.5 (1.9 to 3.3) | 2.9 (2.0 to 4.0) | 1.8 (1.0 to 3.0) | |
| RR (95% CI) | 1.0 | 0.63 (0.32 to 1.18) | 0.13 | |
| ESRD or death (N, %) | 118 (11.6) | 97 (18.3) | 21 (4.3) | <0.0001 |
| Person-years of follow-up for ESRD or death | 19 534 | 11 985 | 7549 | |
| Incidence of ESRD or death (95% CI, /1000 person-years) | 6.0 (5.0 to 7.2) | 8.1 (6.6 to 9.9) | 2.8 (1.7 to 4.2) | |
| RR (95% CI) | 1.0 | 0.34 (0.20 to 0.56) | <0.0001 | |
| ESRD (N, %) | 66 (6.5) | 60 (11.3) | 6 (1.2) | <0.0001 |
| Person-years of duration of T1DM for ESRD | 24 777 | 16 071 | 8706 | |
| Incidence of ESRD (95% CI, /1000 person-years) | 2.7 (2.1 to 3.4) | 3.7 (2.9 to 4.8) | 0.69 (0.25 to 1.5) | |
| RR (95% CI) | 1.0 | 0.18 (0.07 to 0.43) | <0.0001 | |
*The values of HbA1c in group A are shown either at baseline or at the initial consultation in 1980.
BP, blood pressure; ESRD, end-stage renal disease; HbA1c, glycated haemoglobin; RASI, renin angiotensin system inhibitor; RR, rate ratio; T1DM, type 1 diabetes mellitus.