Quality of Lzfe Research, 1, pp. 359-366
Changes in quality of life among persons with HIV infection D. P. Lubeck* and J. F. Fries Department of Medicine, Division of Immunology, Stanford University, Stanford, California 94305, USA.
Health-related quality of life (QOL) is an important component of the evaluation of patient outcome in HIV infection where disease is progressive and debilitating. This paper compares patient-reported QOL obtained from questionnaires which cover functional ability, social functioning, cognition, mental health, disability days, disease symptoms, and overall health in the previous 3 months. These scales have been validated on HIV populations. We compared changes in health status over 12 months for 669 patients with varying HIV disease severity: 134 asymptometic, 416 symptomatic (previously termed ARC), and 119 AIDS. Groups were evaluated at baseline for demographic and health status differences (i.e., age, CD4+). Declines in health status and psychosocial status were found over the year for all persons. Individuals with symptomatic disease or AIDS had significant declines of 10-20% (p < 0.001) in all aspects of role functioning (social, daily activities, energy, and global health) and increased disease symptoms, but no significant declines in cognition or mental health. Persons with AIDS had greater declines than those with symptomatic disease. AIDS and symptomatic patients also reported significantly fewer hours at work and more disability days than asymptomatic patients. The impact that HIV disease has on the health status of non-AIDS symptomatic patients is especially striking.
Key words: AIDS, health status, HIV infection, quality of life.
Introduction Implicit in the concept of patient outcome assessment is a shift from reliance on traditional clinical indicators to a broader definition of health. While health used to be defined primarily in terms of death and increased life expectancy, the emerging conceptualization of health includes evaluation of aspects that might be affected by disease progresThis research was supported by a grant from the Agency for Health Care Policy and Research (HS06211)to James F. Fries, Principal Investigator. This paper was presented at the VIII International Conferenceon AIDS, Amsterdam, July 1992. * To whom correspondence should be addressed. ©1992 Rapld Communications of Oxford Ltd
sion or therapy. The World Health Organization (WHO) defines health as 'not merely the absence of disease, but complete physical, psychological and social well-being.' Thus, health has distinct components--physical health, mental health, everyday social and role functioning, and general perceptions of well-being. Measurement of healthrelated quality of life is now considered an important component of the evaluation of patient outcome. This is especially true for the human immunodeficiency virus (HIV) infection where treatment is only palliative, and the progress of the disease is debilitating and painful, resulting in death. The usefulness of clinical interventions, especially those that may prolong life but not enhance it, must be weighed against the quality of remaining life. Substantial work has been done in other chronic diseases to develop self-administered measures of general health that include sub-scales covering relevant dimensions of health status. These scales do not need to be completed in a clinic setting, and do not involve complex calculations or weightings for combining scales. Self-administered instruments have the advantage of allowing longitudinal assessment of health status in large numbers of patients. Patients may even continue to be followed if they move, change providers, or discontinue care. Relevant instruments that have been applied in studies of outcome in chronic disease include measures of disability, 2 depression, 3 and changes in social, physical, and role functioning 4's developed at Stanford University, and measures developed for the RAND Health Insurance Experiment 6 and the RAND Medical Outcomes Study (MOS). 7-9 Work using these instruments on H W patients has been conducted by Wu and colleagues 1° and Wachtel et al. 11 These studies lend support for the use of these instruments in HIV populations. The purpose of this paper is to: (1) describe the measures of functioning and wellbeing for HIV infection; (2) present self-reported Quality of Life Research . Vol l .1992 359
D. P. Lubeck and J. F. Fries
quality of life among an HIV-infected population with varying disease severity; and (3) compare changes over time for quality-of-life dimensions in patients with differing disease progression.
Methods Outcome assessment
ATHOS (AIDS Time-Oriented Health Outcome Study) is a longitudinal, observational database of HIV-positive and at-risk patients seen by community-based physicians who are ATHOS investigators. Data are collected from two general sources-medical records and patient questionnaires--and are categorized as clinical and outcome data, respectively. Clinical data (medical history, signs, laboratory, diagnosis, and treatment) are abstracted from outpatient and hospital records. Outcome data are collected from a patient selfadministered questionnaire, the AIDS Health Assessment Questionnaire (AIDS-HAQ), which covers the following dimensions: disease-related functional ability, treatment, drug toxicity, health service utilization, and quality of life. Knowledge of the interactions and relative importance of these many and diverse variables is essential to direct patient management approaches and public policies. The original Health Assessment Questionnaire (HAQ) was designed as a generic health status assessment instrument for use in chronic illness and in normal populations which may be supplemented with other scales. The HAQ has been validated for patient self-report in the physician's office, by mail, by telephone, and also for physician rating. 2'12 In developing an appropriate selfadministered instrument to assess the impact of HIV infection on patients, we started with the HAQ and added supplemental scales to focus on dimensions of outcome that were not emphasized otherwise, such as anxiety and depression, energy, social functioning, cognitive functioning, and the presence of HIV-specific symptoms. These dimensions were selected by ATHOS investigators based on clinical experience. The disability section measures functional ability over the past week by asking a total of 27 questions in eleven categories of daily activities: dressing, arising, eating, walking, hygiene, reach, grip, activities, cognition, senses, and driving. For each component question, the level of difficulty is scored from 0 to 3 with 3 equal to unable to 360
Quality of Life Research • Vol 1 • 1992
perform. Each category contains two to three items ascertaining performance, such as the ability to walk up stairs. The highest component score (lowest level of functioning) in each category determines the score for the category. Category scores are averaged to yield an overall Disability Index ranging from 0 to 3.12 For comparative purposes, the Disability Index is transformed to a 0 to 100 continuum with 100 indicating optimal health. The patient is asked to rate and rank overall (global) health on two items. One is a doubleanchored visual analogue scale ranging from 0 = very poor health to 100 = very healthy. The other item asks patients to rank health on an ordinal scale from 1 = excellent to 5 = poor. Validation studies have been conducted to test whether the scales measure functional ability and global health appropriately. 2,12 We also incorporated several scales from the Medical Outcomes Study (MOS), 8'9 an observational study of patient outcomes in different practice settings, and the RAND Health Insurance Experiment (HIE). 6 These scales include items on mental health (anxiety and depression), cognition, and energy, and have demonstrated reliability and validity in general and in chronic disease populations. 6'7"13 Three additional items comprising a scale to measure social functioning (frequency and intensity of social activities, and interactions with friends) were developed especially for use in this study because of the desire to obtain information on the intensity and frequency of interactions. All scales are scored by summing the nonmissing item responses (up to five items in each scale) after reversing scoring of some items, so that a higher score is always indicative of positive health status. All raw scores are then transformed to a 0 to 100 continuum of lowest to highest possible scale scores for comparative purposes. A 4-week time frame for responses was selected. Two other scales from the MOS--a five-item health distress scale and a single question about bodily pain--were recently added to the questionnaire. Twelve-month follow-up on these questions is currently not available, and these data are not reported here. Scale components are summarized in Table 1. Patients also report on the presence (yes or no) of disease symptoms in the past 7 days using a one page checklist of 68 symptoms developed for this study. Symptoms (such as anaemia, night sweats, weight loss, numbness in extremities) were selected by ATHOS physicians who reviewed data
Qual i t y of life and H I V infection Table 1. Components of ATHOS Health Outcome Scales
Measure
No. of items
Disability
11
General health perception Social functioning
2 3
Mental health
5
Cognitive functioning
5
Energy/vitality Symptoms Pain Disease worry
4 68 1 4
Description Extent to which health interferes with daily activities (dressing, arising, eating, walking, hygiene, reach, chores, driving, sight, hearing, memory) Overall ratings of current health in general Extent to which health interferes with the frequency and intensity of normal social activities Extent of psychological well-being (depression, anxiety, and positive well-being) Assessment of cognitive functioning (concentration, reasoning, and memory) Assessment of levels of energy and vitality Presence of HIV-specific symptoms Extent of bodily pain Extent of worry and distress about disease
on patient reports during a 3-month pretest of the questionnaire. Patients are also asked to report on disability days and changes in work associated with illness in order to describe indirect costs of illness.
Patient population
Data collection commences once patients join the study. Clinical, therapeutic, and laboratory data are abstracted at the time of an office visit or hospitalization by a trained abstractor who manages the data bank at each site. A Baseline Information Form is completed both by the patient (self-report) and by the abstractor (based on medical records) and includes data and defining AIDS diagnosis (if relevant), date of HIV infection, and positive test result (if available), date and type of all opportunistic infections, risk category, and demographic information. Hospitalization summaries are requested for all hospital services. Follow-up continues until the patient withdraws from the study or dies. Because study sites were brought 'on-line' in a lagged fashion and because new patients are continually enrolled, length of follow-up varies. Of the 1,575 patients who have complete clinical and questionnaire data, 260 have died, 271 have withdrawn (of which 27 are 'too sick' to participate), and 669 HIV-positive patients have follow-up of 12 months or more. In this paper we present data on patient-reported health status at time of initial questionnaire date (between January 1990 and January 1991) and 12 months later for these 669 patients. Patient status was determined at initial questionnaire and confirmed
by the ATHOS physician, and categories were maintained for this analysis even if patients changed status over the 12 month period. Groups are: 134 patients who are HIV-positive and asymptomatic, 416 symptomatic patients, and 119 patients with AIDS. Data were analysed using the Statistical Analysis System (SAS) for the PC, Version 6.03. An ordinary least squares regression model was used to estimate the impact of disease stage on the quality-of-life measures. The regression method also allowed us to statistically control for other patient characteristics (baseline age and education). Disease stages were defined by d u m m y variables. The excluded category was asymptomatic HIV-positive individuals. All variables were evaluated for the presence and absence of missing data and were found to be consistent across the three groups.
Results Table 2 presents background information on the three groups of patients. Eighteen per cent of the individuals in the study group who are HIV-positive have at least one opportunistic infection that qualifies them for a diagnosis of AIDS, and 62% are symptomatic. Respondents are predominately gay males (98.3%) who are not intravenous drug users, and this distribution does not differ across disease stage. Five patients were infected with HIV through exchange of blood products or heterosexual contact. There are a total of twelve women in this sample. Overall, the ATHOS population is Quality of L~fe Research • Vol 1 • 1992 361
D. P. Lubeck and J. F. Fries
Table 2. Characteristics of 669 ATHOS Participants at Start of Study by Disease Stage HIV+ a n = 134 Mean age (SEM) b Male (%) Risk category (%) Gay/bisexual Other Education level (%)c High school Some college College graduate Postgraduate Ethnicity (%) Black White Latino Other ~
35.2 (0.7) 97.0%
Symptomatic n=416 37.7 (0.4) 98.5%
AIDS n = 119 37.2 (0.8) 98.3%
93.9% 6.1
100.0% -
99.0% 1.0
18.8% 36.8 24.8 19.5
13.8% 39.9 20.9 25.3
19.7% 50.4 18.8 11.1
6.0% 79.7 11.3 3.0
3.4% 85.2 7.1 4.3
5.9% 83.9 7.6 2.6
aHIV-positive patients who have not progressed to symptomatic disease bp < 0.01 for one-way Analysis of Variance cp < 0.01 chi square analysis dlncludes Native Americans, Asians, and others
currently only 8% female, though we have increased efforts to recruit women into the study. Mean age at baseline is 36.6 years (SEM = 0.3) across all groups. Symptomatic patients and persons with AIDS are, on average, 2 years older than asymptomatic patients. The majority of patients have some years of university schooling. Patients are primarily Caucasian (84.1%); the remaining ethnic distribution across the entire sample is 2.6% Hispanic, 4.5% Black, and 0.7% Asian. A total of 37 individuals who had sufficient follow-up have since died. This included 19 individuals with AIDS, 17 individuals classified as symptomatic, and one asymptomatic individual. Results are reported in this analysis for their last reported quality-of-life responses. Time since testing positive for HIV infection was not available for all individuals. Eighty-two per cent of AIDS patients reported an average duration of 48.1 months (SE = 2.1), 77.6% of symptomatic patients reported an average duration of 47.5 months (SE = 1.3), and 64% of asymptomatic patients reported 45.6 months duration (SE = 2.8). Persons with AIDS had a mean time from an AIDS-defining opportunistic infection of 18.3 months (SE = 1.9) and averaged 1.2 opportunistic infections (SE = 0.2). (Data not reported in table.) The average CD4+ lymphocyte count at the start of the study was 471.6 (SE = 32.8) for asymptomatic individuals, 312.4 (SE = 17.2) for sympto362
Quality of L!fe Research • Vol 1 . 1992
matic patients, and 467.7 (SE = 8.2) for AIDS patients. The mean and standard deviation for each of the outcome dimensions, measured at baseline and unadjusted for any group differences, are shown in Table 3. The full range of possible scale scores (0 to 100) was recorded for all the psychosocial measures, but for the health measures of disability, energy and symptoms, no individual reported the lowest possible score of 0. The range for disability was 11 to 100, the range of responses for symptoms was none to 42, and the minimum response for energy was 20 out of 100. The distributions of the psychosocial scores were roughly symmetric in accordance with previous studies. 8 A regression model was estimated for each health measure with the disease groups defined by d u m m y variables. Each model controlled for potential differences due to sociodemographic characteristics (age, education). All estimated scores presented in Tables 4 and 5 represent results for a person with average patient characteristics. Table 4 presents information on adjusted baseline quality-of-life scores for each of the three disease groups. In almost all instances (except the measures of mental health and cognitive functioning) the quality-of-life scales differed significantly (p
Changes in quality of life among persons with HIV infection D. P. Lubeck* and J. F. Fries Department of Medicine, Division of Immunology, Stanford University, Stanford, California 94305, USA.
Health-related quality of life (QOL) is an important component of the evaluation of patient outcome in HIV infection where disease is progressive and debilitating. This paper compares patient-reported QOL obtained from questionnaires which cover functional ability, social functioning, cognition, mental health, disability days, disease symptoms, and overall health in the previous 3 months. These scales have been validated on HIV populations. We compared changes in health status over 12 months for 669 patients with varying HIV disease severity: 134 asymptometic, 416 symptomatic (previously termed ARC), and 119 AIDS. Groups were evaluated at baseline for demographic and health status differences (i.e., age, CD4+). Declines in health status and psychosocial status were found over the year for all persons. Individuals with symptomatic disease or AIDS had significant declines of 10-20% (p < 0.001) in all aspects of role functioning (social, daily activities, energy, and global health) and increased disease symptoms, but no significant declines in cognition or mental health. Persons with AIDS had greater declines than those with symptomatic disease. AIDS and symptomatic patients also reported significantly fewer hours at work and more disability days than asymptomatic patients. The impact that HIV disease has on the health status of non-AIDS symptomatic patients is especially striking.
Key words: AIDS, health status, HIV infection, quality of life.
Introduction Implicit in the concept of patient outcome assessment is a shift from reliance on traditional clinical indicators to a broader definition of health. While health used to be defined primarily in terms of death and increased life expectancy, the emerging conceptualization of health includes evaluation of aspects that might be affected by disease progresThis research was supported by a grant from the Agency for Health Care Policy and Research (HS06211)to James F. Fries, Principal Investigator. This paper was presented at the VIII International Conferenceon AIDS, Amsterdam, July 1992. * To whom correspondence should be addressed. ©1992 Rapld Communications of Oxford Ltd
sion or therapy. The World Health Organization (WHO) defines health as 'not merely the absence of disease, but complete physical, psychological and social well-being.' Thus, health has distinct components--physical health, mental health, everyday social and role functioning, and general perceptions of well-being. Measurement of healthrelated quality of life is now considered an important component of the evaluation of patient outcome. This is especially true for the human immunodeficiency virus (HIV) infection where treatment is only palliative, and the progress of the disease is debilitating and painful, resulting in death. The usefulness of clinical interventions, especially those that may prolong life but not enhance it, must be weighed against the quality of remaining life. Substantial work has been done in other chronic diseases to develop self-administered measures of general health that include sub-scales covering relevant dimensions of health status. These scales do not need to be completed in a clinic setting, and do not involve complex calculations or weightings for combining scales. Self-administered instruments have the advantage of allowing longitudinal assessment of health status in large numbers of patients. Patients may even continue to be followed if they move, change providers, or discontinue care. Relevant instruments that have been applied in studies of outcome in chronic disease include measures of disability, 2 depression, 3 and changes in social, physical, and role functioning 4's developed at Stanford University, and measures developed for the RAND Health Insurance Experiment 6 and the RAND Medical Outcomes Study (MOS). 7-9 Work using these instruments on H W patients has been conducted by Wu and colleagues 1° and Wachtel et al. 11 These studies lend support for the use of these instruments in HIV populations. The purpose of this paper is to: (1) describe the measures of functioning and wellbeing for HIV infection; (2) present self-reported Quality of Life Research . Vol l .1992 359
D. P. Lubeck and J. F. Fries
quality of life among an HIV-infected population with varying disease severity; and (3) compare changes over time for quality-of-life dimensions in patients with differing disease progression.
Methods Outcome assessment
ATHOS (AIDS Time-Oriented Health Outcome Study) is a longitudinal, observational database of HIV-positive and at-risk patients seen by community-based physicians who are ATHOS investigators. Data are collected from two general sources-medical records and patient questionnaires--and are categorized as clinical and outcome data, respectively. Clinical data (medical history, signs, laboratory, diagnosis, and treatment) are abstracted from outpatient and hospital records. Outcome data are collected from a patient selfadministered questionnaire, the AIDS Health Assessment Questionnaire (AIDS-HAQ), which covers the following dimensions: disease-related functional ability, treatment, drug toxicity, health service utilization, and quality of life. Knowledge of the interactions and relative importance of these many and diverse variables is essential to direct patient management approaches and public policies. The original Health Assessment Questionnaire (HAQ) was designed as a generic health status assessment instrument for use in chronic illness and in normal populations which may be supplemented with other scales. The HAQ has been validated for patient self-report in the physician's office, by mail, by telephone, and also for physician rating. 2'12 In developing an appropriate selfadministered instrument to assess the impact of HIV infection on patients, we started with the HAQ and added supplemental scales to focus on dimensions of outcome that were not emphasized otherwise, such as anxiety and depression, energy, social functioning, cognitive functioning, and the presence of HIV-specific symptoms. These dimensions were selected by ATHOS investigators based on clinical experience. The disability section measures functional ability over the past week by asking a total of 27 questions in eleven categories of daily activities: dressing, arising, eating, walking, hygiene, reach, grip, activities, cognition, senses, and driving. For each component question, the level of difficulty is scored from 0 to 3 with 3 equal to unable to 360
Quality of Life Research • Vol 1 • 1992
perform. Each category contains two to three items ascertaining performance, such as the ability to walk up stairs. The highest component score (lowest level of functioning) in each category determines the score for the category. Category scores are averaged to yield an overall Disability Index ranging from 0 to 3.12 For comparative purposes, the Disability Index is transformed to a 0 to 100 continuum with 100 indicating optimal health. The patient is asked to rate and rank overall (global) health on two items. One is a doubleanchored visual analogue scale ranging from 0 = very poor health to 100 = very healthy. The other item asks patients to rank health on an ordinal scale from 1 = excellent to 5 = poor. Validation studies have been conducted to test whether the scales measure functional ability and global health appropriately. 2,12 We also incorporated several scales from the Medical Outcomes Study (MOS), 8'9 an observational study of patient outcomes in different practice settings, and the RAND Health Insurance Experiment (HIE). 6 These scales include items on mental health (anxiety and depression), cognition, and energy, and have demonstrated reliability and validity in general and in chronic disease populations. 6'7"13 Three additional items comprising a scale to measure social functioning (frequency and intensity of social activities, and interactions with friends) were developed especially for use in this study because of the desire to obtain information on the intensity and frequency of interactions. All scales are scored by summing the nonmissing item responses (up to five items in each scale) after reversing scoring of some items, so that a higher score is always indicative of positive health status. All raw scores are then transformed to a 0 to 100 continuum of lowest to highest possible scale scores for comparative purposes. A 4-week time frame for responses was selected. Two other scales from the MOS--a five-item health distress scale and a single question about bodily pain--were recently added to the questionnaire. Twelve-month follow-up on these questions is currently not available, and these data are not reported here. Scale components are summarized in Table 1. Patients also report on the presence (yes or no) of disease symptoms in the past 7 days using a one page checklist of 68 symptoms developed for this study. Symptoms (such as anaemia, night sweats, weight loss, numbness in extremities) were selected by ATHOS physicians who reviewed data
Qual i t y of life and H I V infection Table 1. Components of ATHOS Health Outcome Scales
Measure
No. of items
Disability
11
General health perception Social functioning
2 3
Mental health
5
Cognitive functioning
5
Energy/vitality Symptoms Pain Disease worry
4 68 1 4
Description Extent to which health interferes with daily activities (dressing, arising, eating, walking, hygiene, reach, chores, driving, sight, hearing, memory) Overall ratings of current health in general Extent to which health interferes with the frequency and intensity of normal social activities Extent of psychological well-being (depression, anxiety, and positive well-being) Assessment of cognitive functioning (concentration, reasoning, and memory) Assessment of levels of energy and vitality Presence of HIV-specific symptoms Extent of bodily pain Extent of worry and distress about disease
on patient reports during a 3-month pretest of the questionnaire. Patients are also asked to report on disability days and changes in work associated with illness in order to describe indirect costs of illness.
Patient population
Data collection commences once patients join the study. Clinical, therapeutic, and laboratory data are abstracted at the time of an office visit or hospitalization by a trained abstractor who manages the data bank at each site. A Baseline Information Form is completed both by the patient (self-report) and by the abstractor (based on medical records) and includes data and defining AIDS diagnosis (if relevant), date of HIV infection, and positive test result (if available), date and type of all opportunistic infections, risk category, and demographic information. Hospitalization summaries are requested for all hospital services. Follow-up continues until the patient withdraws from the study or dies. Because study sites were brought 'on-line' in a lagged fashion and because new patients are continually enrolled, length of follow-up varies. Of the 1,575 patients who have complete clinical and questionnaire data, 260 have died, 271 have withdrawn (of which 27 are 'too sick' to participate), and 669 HIV-positive patients have follow-up of 12 months or more. In this paper we present data on patient-reported health status at time of initial questionnaire date (between January 1990 and January 1991) and 12 months later for these 669 patients. Patient status was determined at initial questionnaire and confirmed
by the ATHOS physician, and categories were maintained for this analysis even if patients changed status over the 12 month period. Groups are: 134 patients who are HIV-positive and asymptomatic, 416 symptomatic patients, and 119 patients with AIDS. Data were analysed using the Statistical Analysis System (SAS) for the PC, Version 6.03. An ordinary least squares regression model was used to estimate the impact of disease stage on the quality-of-life measures. The regression method also allowed us to statistically control for other patient characteristics (baseline age and education). Disease stages were defined by d u m m y variables. The excluded category was asymptomatic HIV-positive individuals. All variables were evaluated for the presence and absence of missing data and were found to be consistent across the three groups.
Results Table 2 presents background information on the three groups of patients. Eighteen per cent of the individuals in the study group who are HIV-positive have at least one opportunistic infection that qualifies them for a diagnosis of AIDS, and 62% are symptomatic. Respondents are predominately gay males (98.3%) who are not intravenous drug users, and this distribution does not differ across disease stage. Five patients were infected with HIV through exchange of blood products or heterosexual contact. There are a total of twelve women in this sample. Overall, the ATHOS population is Quality of L~fe Research • Vol 1 • 1992 361
D. P. Lubeck and J. F. Fries
Table 2. Characteristics of 669 ATHOS Participants at Start of Study by Disease Stage HIV+ a n = 134 Mean age (SEM) b Male (%) Risk category (%) Gay/bisexual Other Education level (%)c High school Some college College graduate Postgraduate Ethnicity (%) Black White Latino Other ~
35.2 (0.7) 97.0%
Symptomatic n=416 37.7 (0.4) 98.5%
AIDS n = 119 37.2 (0.8) 98.3%
93.9% 6.1
100.0% -
99.0% 1.0
18.8% 36.8 24.8 19.5
13.8% 39.9 20.9 25.3
19.7% 50.4 18.8 11.1
6.0% 79.7 11.3 3.0
3.4% 85.2 7.1 4.3
5.9% 83.9 7.6 2.6
aHIV-positive patients who have not progressed to symptomatic disease bp < 0.01 for one-way Analysis of Variance cp < 0.01 chi square analysis dlncludes Native Americans, Asians, and others
currently only 8% female, though we have increased efforts to recruit women into the study. Mean age at baseline is 36.6 years (SEM = 0.3) across all groups. Symptomatic patients and persons with AIDS are, on average, 2 years older than asymptomatic patients. The majority of patients have some years of university schooling. Patients are primarily Caucasian (84.1%); the remaining ethnic distribution across the entire sample is 2.6% Hispanic, 4.5% Black, and 0.7% Asian. A total of 37 individuals who had sufficient follow-up have since died. This included 19 individuals with AIDS, 17 individuals classified as symptomatic, and one asymptomatic individual. Results are reported in this analysis for their last reported quality-of-life responses. Time since testing positive for HIV infection was not available for all individuals. Eighty-two per cent of AIDS patients reported an average duration of 48.1 months (SE = 2.1), 77.6% of symptomatic patients reported an average duration of 47.5 months (SE = 1.3), and 64% of asymptomatic patients reported 45.6 months duration (SE = 2.8). Persons with AIDS had a mean time from an AIDS-defining opportunistic infection of 18.3 months (SE = 1.9) and averaged 1.2 opportunistic infections (SE = 0.2). (Data not reported in table.) The average CD4+ lymphocyte count at the start of the study was 471.6 (SE = 32.8) for asymptomatic individuals, 312.4 (SE = 17.2) for sympto362
Quality of L!fe Research • Vol 1 . 1992
matic patients, and 467.7 (SE = 8.2) for AIDS patients. The mean and standard deviation for each of the outcome dimensions, measured at baseline and unadjusted for any group differences, are shown in Table 3. The full range of possible scale scores (0 to 100) was recorded for all the psychosocial measures, but for the health measures of disability, energy and symptoms, no individual reported the lowest possible score of 0. The range for disability was 11 to 100, the range of responses for symptoms was none to 42, and the minimum response for energy was 20 out of 100. The distributions of the psychosocial scores were roughly symmetric in accordance with previous studies. 8 A regression model was estimated for each health measure with the disease groups defined by d u m m y variables. Each model controlled for potential differences due to sociodemographic characteristics (age, education). All estimated scores presented in Tables 4 and 5 represent results for a person with average patient characteristics. Table 4 presents information on adjusted baseline quality-of-life scores for each of the three disease groups. In almost all instances (except the measures of mental health and cognitive functioning) the quality-of-life scales differed significantly (p
