The Nottingham Health Profile: score distribution, internal consistency and validity in asthma and COPD patients.

This cross-sectional study among patients with asthma or Chronic Obstructive Pulmonary Disease (COPD) in general practice examined the psychometric properties of the Nottingham Health Profile (NHP). From 380 asthma patients and 170 COPD patients, data were obtained on the NHP, subjective measurements (i.e. sleep disturbances, problems in performing household activities, dyspnoea) and more objective measurements (peak expiratory flow rate, consultation rate, comorbidity). These data were used to compute score distributions, internal consistency (Cronbach's alpha-coefficient) and construct validity. Score distributions were very skewed, with more than 50% of the patients achieving the best score. The internal consistency was moderate in the asthma group (mean alpha = 0.68) and acceptable in the COPD group (mean alpha = 0.74). Acceptable construct validity was found in both groups. Correlations between the NHP and the subjective measurements were, in general, statistically significant and higher than between the NHP and the more objective measurements. In conclusion, acceptable internal consistency and construct validity implies that the NHP can be used in cross-sectional studies concerning asthma and COPD patients in general practice, and in studies comparing these patients with other patient populations. Further research on the responsiveness of the NHP is needed to justify its use in longitudinal studies.