Table 1.
Baseline characteristics between metformin monotherapy and control groups before and after matching
| Factor | Full cohort with complete case | Propensity score-matched cohort | ||||||
|---|---|---|---|---|---|---|---|---|
| Total (N = 11,293) | MM group (N = 7493) | Control group (N = 3800) | P value | Total (N = 6800) | MM group (N = 3400) | Control group (N = 3400) | P value | |
| Socio-demographic (%, n) | ||||||||
| Age (mean ± SD, n), years | 62.05 ± 10.83 (11,293) | 61.70 ± 10.75 (7493) | 62.75 ± 10.97 (3800) | <0.001* | 62.57 ± 10.78 (6800) | 62.64 ± 10.58 (3400) | 62.51 ± 10.98 (3400) | 0.621 |
| Gender | 0.728 | 0.711 | ||||||
| Female | 59.51 % (6721) | 59.63 % (4468) | 59.29 % (2253) | 59.31 % (4033) | 59.09 % (2009) | 59.53 % (2024) | ||
| Male | 40.49 % (4572) | 40.37 % (3025) | 40.71 % (1547) | 40.69 % (2767) | 40.91 % (1391) | 40.47 % (1376) | ||
| Smoking status | <0.001* | 0.878 | ||||||
| Non-smoker | 92.69 % (10,468) | 91.82 % (6880) | 94.42 % (3588) | 94.04 % (6395) | 94.09 % (3199) | 94.00 % (3196) | ||
| Smoker | 7.31 % (825) | 8.18 % (613) | 5.58 % (212) | 5.96 % (405) | 5.91 % (201) | 6.00 % (204) | ||
| Alcohol status | 0.990 | 0.634 | ||||||
| Non-drinker | 84.77 % (9573) | 84.77 % (6352) | 84.76 % (3221) | 85.03 % (5782) | 85.24 % (2898) | 84.82 % (2884) | ||
| Drinker | 15.23 % (1720) | 15.23 % (1141) | 15.24 % (579) | 14.97 % (1018) | 14.76 % (502) | 15.18 % (516) | ||
| Educational level | 0.235 | 0.672 | ||||||
| No formal education/primary | 60.23 % (6802) | 59.84 % (4484) | 61.00 % (2318) | 61.04 % (4151) | 61.29 % (2084) | 60.79 % (2067) | ||
| Secondary/tertiary | 39.77 % (4491) | 40.16 % (3009) | 39.00 % (1482) | 38.96 % (2649) | 38.71 % (1316) | 39.21 % (1333) | ||
| Clinical parameters (Mean ± SD) | ||||||||
| HbA1c, % | 6.83 ± 0.96 (11,293) | 6.99 ± 1.05 (7493) | 6.52 ± 0.64 (3800) | <0.001* | 6.57 ± 0.64 (6800) | 6.57 ± 0.67 (3400) | 6.58 ± 0.62 (3400) | 0.351 |
| SBP, mmHg | 133.17 ± 16.91 (11,293) | 132.92 ± 17.02 (7493) | 133.67 ± 16.69 (3800) | 0.026* | 133.41 ± 16.77 (6800) | 133.28 ± 16.92 (3400) | 133.54 ± 16.62 (3400) | 0.512 |
| DBP, mmHg | 74.94 ± 10.04 (11,293) | 74.98 ± 10.08 (7493) | 74.84 ± 9.98 (3800) | 0.479 | 74.75 ± 9.97 (6800) | 74.68 ± 10.00 (3400) | 74.83 ± 9.95 (3400) | 0.530 |
| LDL-C, mmol/L | 3.25 ± 0.84 (11,293) | 3.18 ± 0.82 (7493) | 3.40 ± 0.87 (3800) | <0.001* | 3.34 ± 0.84 (6800) | 3.32 ± 0.83 (3400) | 3.35 ± 0.85 (3400) | 0.106 |
| TC/HDL-C Ratio | 4.36 ± 1.26 (11,293) | 4.31 ± 1.13 (7493) | 4.45 ± 1.46 (3800) | <0.001* | 4.39 ± 1.16 (6800) | 4.38 ± 1.13 (3400) | 4.41 ± 1.18 (3400) | 0.327 |
| Triglyceride, mmol/L | 1.65 ± 0.89 (11,293) | 1.68 ± 0.91 (7493) | 1.59 ± 0.85 (3800) | <0.001* | 1.60 ± 0.83 (6800) | 1.60 ± 0.78 (3400) | 1.60 ± 0.87 (3400) | 0.914 |
| BMI, kg/m2 | 25.63 ± 3.91 (11,293) | 25.69 ± 3.89 (7493) | 25.51 ± 3.94 (3800) | 0.018* | 25.59 ± 3.85 (6800) | 25.56 ± 3.72 (3400) | 25.61 ± 3.98 (3400) | 0.665 |
| Stage of CKD (%, n) | <0.001* | 0.711 | ||||||
| Stage 1 | 35.74 % (4036) | 37.89 % (2839) | 31.50 % (1197) | 32.85 % (2234) | 32.62 % (1109) | 33.09 % (1125) | ||
| Stage 2 | 55.98 % (6322) | 54.16 % (4058) | 59.58 % (2264) | 58.71 % (3992) | 59.15 % (2011) | 58.26 % (1981) | ||
| Stage 3 | 8.28 % (935) | 7.95 % (596) | 8.92 % (339) | 8.44 % (574) | 8.24 % (280) | 8.65 % (294) | ||
| Disease characteristics (%, n) | ||||||||
| Duration of DM | <0.001* | 0.652 | ||||||
| <5 years | 63.91 % (7217) | 59.72 % (4475) | 72.16 % (2742) | 70.03 % (4762) | 70.06 % (2382) | 70.00 % (2380) | ||
| 5–10 years | 23.84 % (2692) | 26.37 % (1976) | 18.84 % (716) | 20.50 % (1394) | 20.76 % (706) | 20.24 % (688) | ||
| >10 years | 12.26 % (1384) | 13.91 % (1042) | 9.00 % (342) | 9.47 % (644) | 9.18 % (312) | 9.76 % (332) | ||
| Hypertension | <0.001* | 0.669 | ||||||
| No | 28.30 % (3196) | 31.59 % (2367) | 21.82 % (829) | 23.81 % (1619) | 24.03 % (817) | 23.59 % (802) | ||
| Yes | 71.70 % (8097) | 68.41 % (5126) | 78.18 % (2971) | 76.19 % (5181) | 75.97 % (2583) | 76.41 % (2598) | ||
| Treatment modalities (%, n) | ||||||||
| Use of anti-hypertensive drugs | <0.001* | 0.956 | ||||||
| No | 29.33 % (3312) | 31.06 % (2327) | 25.92 % (985) | 26.41 % (1796) | 26.38 % (897) | 26.44 % (899) | ||
| Yes | 70.67 % (7981) | 68.94 % (5166) | 74.08 % (2815) | 73.59 % (5004) | 73.62 % (2503) | 73.56 % (2501) | ||
| Use of lipid-lowering agents | 0.032* | 0.699 | ||||||
| No | 95.71 % (10809) | 95.42 % (7150) | 96.29 % (3659) | 96.32 % (6550) | 96.41 % (3278) | 96.24 % (3272) | ||
| Yes | 4.29 % (484) | 4.58 % (343) | 3.71 % (141) | 3.68 % (250) | 3.59 % (122) | 3.76 % (128) | ||
MM metformin monotherapy, HbA1c haemoglobin A1c, SBP systolic blood pressure, DBP diastolic blood pressure, LDL-C low density lipoprotein—cholesterol, TC Total cholesterol, HDL-C high density lipoprotein-cholesterol, BMI body mass index, eGFR estimated glomerular filtration rate, DM diabetes mellitus, CKD chronic kidney disease
Stage 1 CKD (eGFR ≥90 ml/min/1.73 m2); Stage 2 CKD (eGFR ≥60 & <90 ml/min/1.73 m2); Stage 3 CKD (eGFR ≥30 & <60 ml/min/1.73 m2)
* Significant with p value < 0.05 by Chi-square test or t test as appropriate