[Development of a scale for subjective QOL common to patients with intractable diseases]

We have developed a scale for evaluating subjective quality of life (QOL) common to patients with intractable diseases.

Two-hundred and forty-seven outpatients of housebound patients from 7 collaborating hospitals or institutions participated in preliminary surveys. The patients were diagnosed with one of 14 diseases targeted by the Ministry of Health and Welfare's Specific Disease Treatment Research Project. Two-hundred and fifty-seven outpatients or housebound patients of 8 collaborating hospitals or institutions participated in a second survey that targeted 15 diseases.

The concept of subjective QOL was examined, and a favorable subjective QOL score was defied as "a state in which patients accept their current condition and possess a high level of morale with no signs of anxiety, despite the presence of their disease". Sixty-six items were then identified and included in a preliminary survey. Three preliminary surveys and a second survey were then conducted. A final scale for the items was then decided, and the items were assessed for their reliability and validity.

Nine items reflecting two factors, "acceptance" and "morale", were selected and assessed for their reliability and validity as follows: 1) The response of subjects who accepted their illness yet possessed a high level of morale showed a good fit with the proposed scale (Adjusted Goodness of Fit Index = 0.925). 2) The confidence coefficient of the re-test method for subjective QOL scale scores was r = 0.78 (95% con idence interval: 0.72-0.83; n = 226) nd the alpha coefficient was 0.822, indicating a high level of reliability. 3) A strong negative correlation (r = -0.76, 95% confidence interval: -0.82 to -0.69; n = 178) was found between the subjective QOL scale scores and self-rating depression scale (SDS) scores, and a moderately positive correlation (r = 0.35, 95% confidence interval: 0.23-0.46; n = 238) was found between the subjective QOL scale scores and activities of daily living (ADL) scores. 4) No statistically significant differences were observed in the distribution of subjective QOL scale scores when analyzed according to sex, age group, disease, or duration of illness.

We have developed a scale consisting of 9 items for determining the subjective QOL of patients with intractable diseases. The scale was confirmed to properly reflect our concept of subjective QOL, which consists of two factors: "acceptance" and "morale" The scale was also confirmed to be stable and highly reliable.