Table 3

Subgroup analyses for studies reporting adjusted effect estimates

SubgroupsNo. of studiesOR (95% CI)P valueI2 P value for within-stratum heterogeneityP value for between-stratum heterogeneity
Compared groups
 Insulin versus oral drugs61.42 (1.08 to 1.86)<0.0571.3%<0.050.28
 Insulin versus non-drugs20.87 (0.37 to 2.03)>0.0566.5%0.08
Degree of adjustment
 +++101.43 (1.08 to 1.89)<0.0568.9%<0.050.44
 ++21.24 (0.98 to 1.55)>0.0525.3%0.25
Region
 USA40.86 (0.57 to 1.31)>0.0536.4%0.190.12
 Asia51.81 (1.18 to 2.79)<0.0559%0.05
 Europe21.58 (0.85 to 2.94)>0.0592.9%<0.05
 Africa11.53 (0.99 to 2.37)>0.05
Identification of depression
 Self-report questionnaire101.42 (1.06 to 1.91)<0.0568.9%<0.050.69
 Medical records21.31 (1.00 to 1.71)>0.0565.6%0.09
Sample size
 ≥100041.46 (1.10 to 1.94)<0.0573.1%<0.050.72
 <100081.34 (0.93 to 1.93)>0.0570%<0.05
Mean age, years
 ≥60.051.12 (0.77 to 1.62)>0.0578.8%<0.050.08
 <60.061.74 (1.24 to 2.43)<0.0550.8%0.07
Percentage male (%)
 ≥50.071.26 (0.97 to 1.63)>0.0562.4%<0.050.14
 <50.051.71 (1.25 to 2.35)<0.0553.9%0.07
Prevalence of depression
 ≥20%71.48 (1.12 to 1.96)<0.0571.3%<0.050.53
 <20%51.25 (0.80 to 1.95)>0.0572.7%<0.05
NOS
 7 or 881.25 (0.94 to 1.66)>0.0560.0%<0.050.19
 <741.79 (1.14 to 2.80)<0.0584.6%<0.05
  • NOS, Newcastle-Ottawa Scale.