Table 2 Correlations between symptoms and patient characteristics

From: Morning and night symptoms in primary care COPD patients: a cross-sectional and longitudinal study. An UNLOCK study from the IPCRG

 nMorning symptomsaNight symptomsb
  rProportion explained variance (r2)rProportion explained variance (r2)
 Age of onset1,992−0.050%−0.020%
 FEV1 predicted2,227−0.163%−0.11%
 FEV1/FVC predicted2,224−0.111%−0.030%
 Mean number of exacerbations last year2,2280.132%0.121%
 Night symptoms (ACQ question 1)2,2330.5328%1100%
 Morning symptoms (ACQ question 2)2,2311100%0.5328%
 Sputum production (CCQ question 6)2,2310.4621%0.3915%
 Wheezing (ACQ question 5)2,2320.4520%0.4419%
Health status
 CCQ subscale functional status2,2330.4419%0.3915%
 CCQ subscale mental status2,2300.4117%0.3915%
 CCQ subscale symptoms2,2320.5935%0.5227%
 CCQ total scale2,2290.5834%0.5227%
  1. Abbreviations: ACQ, Asthma Control Questionnaire; CCQ, COPD Clinical Questionnaire; COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.
  2. aACQ question 2.
  3. bACQ question 1.