Paper
Associations of Symptoms and Health-Related Quality of Life: Findings from a National Study of Persons with HIV Infection
Published May 1, 2001 · K. Lorenz, M. Shapiro, S. Asch
Annals of Internal Medicine
159
Citations
5
Influential Citations
Abstract
A symptom indicates disorder or disease and has been defined as a patient's perception of an abnormal physical, emotional, or cognitive state (1). Symptom assessment is a central task of the physician during the physicianpatient encounter because symptoms compel patients to seek health care and identify possibilities for specific diagnostic and therapeutic interventions. Health-related quality of life, in contrast, refers to general function and well-being but is less familiar to clinicians and is not assessed in routine patient care. This is interesting when we consider that symptoms have also been described as a change from normal function, sensation, or appearance (2) and that health-related quality of life is also used to measure change in function or well-being. Health-related quality-of-life measures designed for research purposes often include symptoms. For example, the widely used Short Form-36 Health Survey (3) includes items assessing pain, fatigue, and depressive symptoms. The Quality of Well-Being Scale includes symptomproblem complexes as one of its four domains, and symptoms contribute substantially to the derivation of the 0 to 1 preference score (4). For example, a burning or itching rash decreases the preference score by 0.240 compared with the 0.106 decrement associated with the inability to perform self-care activities. Disease-targeted measures often ask about many symptoms. For example, the Kidney Disease Quality of Life instrument includes 34 symptomproblem questions (5). Several studies suggest that symptoms and measures of functioning and well-being are empirically correlated (6). A recent analysis of a national sample of patients receiving care for HIV infection revealed a strong monotonic association between HIV-related symptoms and impaired functioning and well-being (7). Each additional symptom was associated with a mean (SD) decrease of approximately 1.5 10 points in physical and mental health-related quality-of-life summary scores. However, this previous study did not investigate whether some symptoms are more strongly associated with physical and mental health than other symptoms. Methods Study Design We evaluated a national probability sample of adults with known HIV infection who made at least one visit to a nonmilitary, nonprison medical provider other than an emergency department in early 1996. From all patients receiving care from 145 HIV providers in 28 metropolitan areas and 51 providers in 25 rural areas throughout the United States, a random sample was selected for face-to-face interviews. Of 4042 eligible participants sampled, 2864 (71%) were interviewed during the baseline study. Two follow-up surveys were conducted, the second between August 1997 and January 1998. Our study evaluated the 2267 patients who responded to both the baseline and second follow-up surveys. Deaths were confirmed by interviews with patient proxies or the patient's physician or were documented through the National Death Index. Further details of the study design were reported elsewhere (8, 9). Measures Symptoms Symptoms were selected for inclusion after review of previous research and symptom screens used in HIV clinical trials and incorporating expert judgments of HIV clinicians and community representatives. We constructed an index by summation across 13 symptoms in men and 14 symptoms in women. Symptoms assessed in both men and women included headache; fever, sweats, or chills; pain in the mouth, lips, or gums; white patches in the mouth; dry mouth; genital rashes or sores; nausea or loss of appetite; trouble with eyes; sinus infection, pain, or discharge; pain, numbness, or tingling of hands or feet; persistent cough, difficulty breathing, or difficulty catching one's breath for more than 1 week; diarrhea or loose or watery stools; and weight loss. Women were also asked about the presence of vaginal discharge. All patients were asked about the presence of symptoms since their previous follow-up interviews, an interval that averaged approximately 6 months. Total symptom scores in men and women were standardized by sex to a possible range of 0 to 14. Health-Related Quality of Life and Disability Days We evaluated two single global items assessing major components of health-related quality of life. We selected these measures to avoid the problem of direct inclusion of symptom items, which characterizes many health-related quality-of-life instruments. The questions were as follows: 1) Overall, how would you rate your current health? 2) Overall, how would you rate your quality of life? Both of these items used a response scale of 0 to 10, where 0 represents the worst possible score, 5 is halfway between worst and best, and 10 represents the best possible score. The response scale was adapted from the global ratings items included in the Consumer Assessment of Health Plans Study (10), and all responses were transformed to a scale of 0 to 100. We also assessed disability days, defined as a day in which at least half of the patient's time was spent in bed because of poor health. Each of these three items was administered by using a 4-week reporting period. Statistical Analyses The probability of selecting a respondent is a function of the likelihood of selecting a patient from a particular geographic area cared for by a particular HIV provider from among the total population of persons eligible for inclusion in the study. Analysis weights adjust for these sampling factors as well as for attrition due to nonresponse for causes other than death. Although it does not account for persons in the cohort who died during the follow-up interval, statistical weighting ensures that the cohort analyzed in our study represents as much as possible the larger population of HIV-infected patients in the United States (11). We adjusted standard errors for the differential weighting and complex sample design using linearization methods (12). We used randomly drawn donor responses within strata of respondents (hot deck imputation) to fill in the less than 5% of essential missing values (13). We used multiple linear regression to evaluate the independent associations of each symptom with perceived health, perceived quality of life, and disability days. All models were adjusted for the presence of other symptoms and sociodemographic characteristics, including age, sex, ethnicity, education, marital status, income, employment status, health insurance, risk group, stage of illness, region of the United States, and lowest reported CD4 lymphocyte count. Model fitting included the evaluation of all possible interactions; only interactions with a P value less than 0.05 were retained. We report significance tests of both linear terms with their corresponding interaction terms. All analyses were conducted by using Stata 5.0 software (Stata Corp., College Station, Texas). Role of the Funding Sources The funding sources had no role in the collection, analysis, or interpretation of the data or in the decision to submit the manuscript for publication. Results Of the 4042 eligible persons sampled, 2864 (71%) completed the baseline survey. Of those participating in the baseline survey, 2466 (86%) completed the first follow-up survey and 2267 (79%) completed the second follow-up survey. The characteristics of the 2267 persons interviewed for our study are described in Table 1. The 238 persons lost to follow-up because of confirmed death had poorer baseline health than survivors. Table 1. Characteristics of the Analytic Sample The associations of each of the 14 symptoms with perceived health, perceived quality of life, and disability days at second follow-up are shown in Table 2. Regression coefficients and 95% CIs are provided. Eight symptoms (headache; pain in mouth, lips, or gums; white patches in the mouth; dry mouth; nausea or loss of appetite; sinus infection, pain, or discharge; persistent cough, difficulty breathing, or difficulty catching one's breath; and weight loss > 2.25 kg) were associated with worse perceived health scores. Eight symptoms (pain in mouth, lips, or gums; white patches in the mouth; nausea or loss of appetite; trouble with eyes; pain, numbness, or tingling of hands or feet; persistent cough, difficulty breathing, or difficulty catching one's breath; diarrhea or loose or watery stools; and weight loss > 2.25 kg) were associated with worse perceived quality of life. Six symptoms (headache; fever, sweats, or chills; white patches in the mouth; nausea or loss of appetite; persistent cough, difficulty breathing, or difficulty catching one's breath; and weight loss of >2.25 kg) were associated with more disability days. On average, patients with sinus infection, pain, or discharge had higher perceived quality of life, although this was a suppression effect (the correlation was negative but the -coefficient was positive). At the second follow-up, an asymptomatic patient experienced an average quality-of-life score of 93, an average perceived health score of 82, and 0.33 disability day. Compared with the average asymptomatic respondent, among symptomatic patients white patches in the mouth were associated with 4% lower perceived health scores, 6% lower perceived quality-of-life scores, and 1.02 additional disability days. Nausea was associated with 5% lower perceived health scores, 8% lower perceived quality-of-life scores, and 1.03 additional disability days. Dyspnea was associated with 7% lower perceived health scores and 8% lower perceived quality-of-life scores. Weight loss was associated with 3% lower perceived health scores and 4% lower perceived quality-of-life scores. Both dyspnea and weight loss were associated with additional disability days. Table 2. Multivariable Associations of Symptoms with Perceived Health, Perceived Quality of Life, and Disability Days We tested for the presence of statistically significant interactions to assess the possibility that symptoms may be associated differently with healt
Observational Study
Highly CitedSymptoms are strongly associated with impaired physical and mental health-related quality of life in HIV patients, with some symptoms being more strongly associated than others.
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