Table 1.
Characteristics of the included observational studies.
| Study | Country | Study design | Participants | Sample size | Mean age years | Male | Lp (a) presentation | Follow-up duration years | Definition of DN | Variables adjusted | Quality score |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Song et al. (12) | Korea | PC | T2DM patients | 81 | 59 | 44 | Continuous | 2 | > 2-fold increase of follow-up SCr | Baseline SCr, SBP, and HbA1c | 7 |
| Tseng (18) | China | CS | T2DM patients | 549 | 63 | 45 | Continuous | NA | Microalbuminuria (ACR: 30–299 μg/mg) and macroalbuminuria (ACR ≥300 μg/mg) | Age, sex, BMI, diabetic duration, insulin use, SBP, use of statin/fibrate and use of ACEI/ARB | 8 |
| Lin et al. (19) | USA | PC | T2DM women | 516 | 69 | 0 | Q4 vs. Q1 | 11 | eGFR decline of ≥ 25% during follow-up | Age, hypertension, BMI, ever smoked, physical activity, duration of T2DM, use of ACEI/ARB, baseline HbA1c and eGFR | 9 |
| Lin et al. (13) | USA | CS | T2DM patients without clinical CVD and with eGFR > 60 ml/min/1.73m2 | 1852 | 59 | 64 | Continuous, and ≥ 30 mg/dl vs. < 30mg/dl | NA | eGFR: 60–90 ml/min/1.73m2 | Age, sex, race, BMI, hypertension, lipid-lowering medications, HbA1c, HOMA-IR, duration on insulin, and urinary ACR | 8 |
| Yun et al. (15) | Korea | PC | T2DM patients with eGFR > 90 ml/min/1.73m2 | 560 | 53 | 40 | T3 vs. T1 | 10 | eGFR < 60 ml/min/1.73m2 | Age, sex, diabetes duration, the presence of hypertension, CVD history, smoking, BMI, mean HbA1c, diabetic microvascular complication, FPG and Lp(a)-corrected LDL-C and medications like insulin, ACEI/ARB, statin, fenofibrate and acetylsalicylic acid | 9 |
| Senba et al. (14) | Japan | CS | T2DM patients | 581 | 60 | 65 | Above 90th percentile vs. below 30th percentile | NA | ACR ≥300 μg/mg and/or eGFR < 30 ml/min/1.73m2 | Age, sex, BMI, HbA1c, duration of T2DM, current drinking, current smoking, hypertension, dyslipidemia, CAD, and stroke | 8 |
| Aryan et al. (20) | Iran | NCC | T2DM patients | 939 | 58 | 48 | Continuous, and Q4 vs. Q1 | NA | Microalbuminuria (ACR: 30–299 μg/mg), macroalbuminuria (ACR ≥300 μg/mg), or eGFR < 60 ml/min/1.73m2 | Age, sex, BMI, duration of diabetes, FPG, HbA1c, SBP, and the use of antihyperglycemic, antihypertensive and lipid-lowering medications | 8 |
| Singh et al. (22) | the Netherlands | PC | T2DM patients | 1850 | 65 | 54 | ≥ 30 mg/dl vs. < 30mg/dl | 7 | Microalbuminuria (ACR: 30–299 μg/mg) and macroalbuminuria (ACR ≥300 μg/mg) | Age, sex, MAP, non-HDL-cholesterol, HDL-cholesterol, BMI, duration of type 2 diabetes, HbA1c and smoking | 8 |
| Heinrich et al. (21) | Denmark | PC | T2DM patients | 198 | 59 | 74 | Continuous | 6 | eGFR decline of ≥ 30% during follow-up | Age, sex, SBP, LDL-C, smoking, HbA1c, SCr and ACR | 7 |
| Xuan et al. (17) | China | PC | T2DM patients | 1121 | 58 | 37 | T3 vs. T1-2 | 4 | eGFR < 60 ml/min/1.73m2 | Age, sex, BMI, FPG, SBP, TG, HDL-C, LDL-C, eGFR, smoking and drinking status, and use of antihypertensive drugs and antidiabetic drugs | 9 |
| Moosaie et al. (16) | Iran | NCC | T2DM patients | 1057 | 57 | 47 | Continuous, and ≥ 34 mg/dl vs. < 34 mg/dl | NA | eGFR < 44 ml/min/1.73m2 | Age, sex, SBP, HbA1c, BMI, use of anti-dyslipidemic drugs, eGFR, TG, LDL-C, HDL-C, non-HDL cholesterol, and waist/hip ratio | 8 |
Lp (a), lipoprotein (a); DN, diabetic nephropathy; PC, prospective cohort; CS, cross-sectional; NCC, nested case-control; T2DM, type 2 diabetes mellitus; CVD, cardiovascular diseases; eGFR, estimated glomerular filtrating rate; Q, quartile; T, tertile; NA, not applicable; SCr, serum creatinine; ACR, albumin creatinine ratio; SBP, systolic blood pressure; HbA1c, glycated hemoglobulin; BMI, body mass index; ACEI, angiotensin converting enzyme inhibitor; ARB, angiotensin II receptor blocker; HOMA-IR, homeostasis model assessment of insulin resistance; FPG, fasting plasma glucose; LDL-C, low-density lipoprotein cholesterol; CAD, coronary artery disease; HDL-C, high-density lipoprotein cholesterol; TG, triglyceride; MAP, mean arterial pressure.