Table 4

Overall effects and subgroup analyses for medication adherence interventions

kNORCII² (%)P heterogeneityP bias
Overall
 All studies2397351.541.26 to 1.8857.50.0010.066
 Excluding outliers2195451.411.21 to 1.6535.30.0570.286
Interventionist
 Pharmacist68131.440.92 to 2.2630.00.2100.309
 No pharmacist1587321.411.19 to 1.6841.00.0490.439
 Nurse1150301.191.04 to 1.3600.9200.501
 No nurse1045151.631.26 to 2.1052.10.0270.454
 Other HCPs538421.661.22 to 2.2467.10.0120.550
 Nurse or pharmacists1657031.211.07 to 1.3800.6630.167
Delivery method
 In person only963581.211.08 to 1.3600.8900.305
 Included phone contact1231871.631.25 to 2.1232.00.1350.629
Theoretical basis
 Theory based46860.940.60 to 1.4900.7810.692
 Not theory based1788591.481.25 to 1.7641.40.0380.094
Outcome
 Primary1238331.311.11 to 1.5400.6220.227
 Secondary957121.481.12 to 1.9663.10.0060.548
Risk of bias
 Low risk639481.691.15 to 2.4751.40.0680.042
 Higher risk1555971.361.13 to 1.6428.10.1470.658
  • HCP, healthcare provider; I²,  heterogeneity; k, number of studies; N, sample size; P  bias,  small study effects significance; P heterogeneity, heterogeneity significance.

  • Interventionist, delivery method and theoretical basis were prespecified subgroups, while outcome and risk of bias were determined post hoc. Outliers were excluded from subgroup analyses.40 45