Purpose: The Health & Activity Limitation Index (HALex) was introduced in 1995 to measure health-related quality of life (HRQoL) for Healthy People 2000 and has been used for population tracking activities and in a few research studies. However, little is known about how HALex scores relate to other measures of HRQoL. The purpose of this study was to equate scores on the HALex with scores on an accepted measure of HRQoL, the Quality of Well-Being (QWB) scale.

Methods: We administered the HALex and QWB questions to a sample of 401 adults in St. Louis Missouri. We used random-digit-dial techniques to select a random sample of 302 adults from the St. Louis Metropolitan area, and enriched this sample by recruiting 99 participants with mobility impairments. Inclusion of the mobility-impaired participants provided representation of a broader range of disability than would typically be found in a randomly selected population. We used multiple regression analysis to examine the relationship between HALex and QWB scores, and to see how demographic and health status factors influenced this relationship.

Results: In this sample, scores on the QWB and HALex were similar on mid-range values and discrepant at the extremes, i.e. persons with extreme HALex scores tended to have more moderate QWB scores. For instance, participants with a score of 1.0 on the HALex had a mean score of 0.76 on the QWB, and participants with a mean score of 0.10 on the HALex had a mean score of 0.42 on the QWB. QWB scores alone accounted for 39% of the variance in HALex scores; the addition of five demographic and health factors increased the variance explained to 63%. HALex scores were higher for white adults than predicted by their QWB score, and HALex scores for people with chronic diseases and disabilities were lower than predicted.

Conclusion: HRQoL scores assigned by the HALex and QWB to the same case can vary markedly, particularly if the individual is extremely healthy or unhealthy. Including information about a few demographic and health-related characteristics greatly improves our ability to predict HALex scores from QWB scores, suggesting that there are systematic differences in how the two scales evaluate HRQoL which require further investigation.