Table 4

Subgroup analyses for studies reporting crude effect estimates

SubgroupsNo. of studiesOR (95% CI)P valueI2 (p value)P value for within-stratum heterogeneityP value for between-stratum heterogeneity
Compared groups
 Insulin versus oral drugs171.61 (1.35 to 1.93)<0.0562.6%<0.050.49
 Insulin versus non-drugs61.89 (1.25 to 2.88)<0.0568.2%<0.05
Region
 USA41.53 (1.21 to 1.93)<0.0575.4%<0.050.31
 Asia91.60 (1.22 to 2.10)<0.0575.4%0.05
 Europe71.59 (1.13 to 2.22)<0.0545.3%<0.05
 Africa21.77 (1.23 to 2.54)<0.050.00.85
 South America11.28 (0.50 to 3.27)>0.05
Sample size
 ≥100071.64 (1.39 to 1.93)<0.0577.5%<0.050.71
 <1000171.56 (1.27 to 1.91)<0.0546.7%<0.05
Mean age
 ≥60.0101.60 (1.30 to 1.97)<0.0561.8%<0.050.92
 <60.0101.57 (1.18 to 2.09)<0.0568.0%<0.05
Percentage male (%)
 ≥50.0131.59 (1.29 to 1.96)<0.0575.1%<0.050.82
 <50.0111.55 (1.43 to 1.68)<0.050.00.71
Prevalence of depression
 ≥20%141.84 (1.59 to 2.12)<0.0511.7%0.33<0.05
 <20%101.43 (1.19 to 1.70)<0.0574.0%<0.05
Newcastle-Ottawa Scale
 7 or 8111.45 (1.16 to 1.82)<0.0572.3%<0.050.22
 <7131.72 (1.47 to 2.00)<0.0542.8%0.05