Table 3

Meta-analysis: correlations reported for health-related quality of life with clinical measures

Clinical measuresKNMeta-analysis correlation mean r (95% CI)Q testI2 (%)Rosenthal's N
Cough21240.57 (−0.03 to 0.87); p=0.0607.56; p=0.00686.8*20†
Dyspnoea712160.55 (0.41 to 0.68); p<0.00154.42; p<0.00189.0*792
Wheeze22130.42 (0.30 to 0.53); p<0.0010.27; p=0.6020.029
Fatigue41820.42 (0.23 to 0.58); p<0.0014.72; p=0.19436.440
Exercise capacity111038−0.41 (−0.54 to −0.24); p<0.00150.81; p<0.00180.3*419
Depression75720.41 (0.23 to 0.55); p<0.00127.53; p<0.00178.2*220
Sputum volume34020.36 (0.24 to 0.47); p<0.0013.39; p=0.18441.057
Pseudomonas presence/colonisation21890.36 (0.23 to 0.48); p<0.0010.70; p=0.4010.018†
CT bronchiectasis scores913380.35 (0.03 to 0.61); p<0.001253.63; p<0.00196.8*856
Oxygen saturation4324−0.35 (−0.44 to −0.24); p<0.0010.46; p=0.9280.051
Anxiety55140.34 (0.19 to 0.47); p=0.02511.38; p=0.02364.9‡97
Hospital admissions rate26950.34 (0.16 to 0.49); p<0.0012.95; p=0.08666.1‡55
FEV1%172228−0.31 (−0.40 to −0.23); p<0.00159.32; p=0.00073.0‡990
Infections/exacerbations rate814980.31 (0.24 to 0.38); p=0.00112.99; p=0.07246.1380
FVC%71031−0.30 (−0.41 to −0.19); p<0.00114.39; p=0.02658.3‡182
Any microbiological presence/colonisation37580.26 (0.19 to 0.33); p<0.0010.43; p=0.8050.043
Sputum colour22040.25 (0.05 to 0.43); p=0.0131.91; p=0.16747.67†
Comorbidities28150.09 (0.02 to 0.16); p=0.0140.44; p=0.5080.03†
  • For the purposes of comparison, higher score indicates poorer health-related quality of life.

  • Statistical heterogeneity among the studies was assessed using the Q test and quantified using the I2.

  • I2, Indicates the percentage of total variation across studies that is due to heterogeneity rather than chance. I2 value of 0% was considered to indicate no observed heterogeneity.

  • *I2 between 75–100% may represent considerable heterogeneity.

  • †Rosenthal's Number lower than 5×knumber_of_studies+10 indicates publication bias of the studies included in the meta-analysis.

  • ‡I2 between 30–60% may represent moderate heterogeneity among the studies according to Cochrane manual.

  • K, number of studies; N, number of overall participants; Q, Cochran's Q test, which examines the null hypothesis that all studies are evaluating the same effect; r, correlation coefficient.