90 1 SOCIAL AND ECONOMIC IMPACTS OF FOUR MUSCULOSKELETAL CONDITIONS A Study Using National Community-Based Data JANE S. KRAMER, EDWARD H. YELIN, and WALLACE V . EPSTEIN The present study uses data from a national, community-based survey to compare the social impact of and medical care use due to 4 musculoskeletal conditions: rheumatoid arthritis, osteoarthritis, lower back pain, and tendinitis. The study also compares the impacts experienced by persons with these conditions with those experienced by a sample of persons having a broader range of musculoskeletal conditions, and by an age-adjusted sample representing the entire U.S. population. Rheumatoid arthritis leads to the most frequent use of physician services; lower back pain results in the most hospitalizations and surgery. Rheumatoid arthritis also causes the most restriction in activity. We found that as a broad group, persons with musculoskeletal disease experience about the same amount of restriction in activity and use about the same amount of medical care as U.S. citizens as a whole. This study demonstrates that health planning on the basis of specific musculoskeletal conditions is necessary to serve the disparate needs of persons with particular, discrete conditions. The impacts of musculoskeletal disease as a whole have been well documented. We know, for example, that musculoskeletal conditions rank second to circulatory diseases in restricting activities ( l ) , From the Social Science Research Component, Multipurpose Arthritis Center, the Robert Wood Johnson Clinical Scholars Program, and the Institute for Health Policy Studies, University of California, San Francisco. Supported in part by Grant No. AM-20684 from the National Institutes of Arthritis, Diabetes, and Digestive and Kidney Diseases, and by the Robert Wood Johnson Foundation, Princeton, New Jersey. Address reprint requests to Jane Kramer, MSc, 350 Parnassus Avenue, Suite 407, San Francisco, CA 941 17. Submitted for publication August 9, 1982: accepted in revised form March 1, 1983. Arthritis and Rheumatism, Vol. 26, No. 7 (July 1983) make up 41% of the persons referred to vocational rehabilitation (2), and are the second most frequent cause of work disability, accounting for 15% of all those claiming to be work disabled (1). Musculoskeletal conditions also account for 20% of Medicare hospital costs (3), and are the second most frequent cause of outpatient physician visits among all chronic conditions (4). Kelsey et a1 point out that musculoskeletal conditions rank highly on all measures of disease impact, except mortality ( 5 ) . The impacts of musculoskeletal conditions as a group have been relatively well identified, as have some of the impacts of particular conditions in clinical samples, such as hospital or academic medical settings (6-8). The impacts of particular musculoskeletal conditions in the community at large, however, have not been well documented. The purpose of this paper is threefold: we first describe some of the social and medical characteristics of persons with one of 4 common musculoskeletal conditions: rheumatoid arthritis (RA), osteoarthritis (OA), lower back pain (LBP), and tendinitis (TEN). We then describe the impacts of these conditions and compare them with the impacts experienced by a sample of persons having a broad range of musculoskeletal diseases. In doing this we are able to determine whether the impacts of musculoskeletal disease broadly defined are significantly different from the impacts of these 4 discrete musculoskeletal conditions. Finally, we compare the impacts of the 4 distinct musculoskeletal conditions with those experienced by an age-adjusted sample which represents the entire United States population regardless of health status. The purpose of this is to understand the extent to which persons with these discrete musculoskeletal conditions, and with those more broadly defined, are KRAMER ET A L different from similarly aged U.S. citizens in ability to perform work and other daily activities and in use of medical care. METHODS The data for this paper are derived from the 1976 National Health Interview Survey (NHIS) (9),administered by the National Center for Health Statistics. The NHIS is an annual survey of the civilian, noninstitutionalized population of the continental U.S., and includes approximately 115,000 persons in 42,000households. The interviews for the NHIS, which are conducted in person, collect information on social and demographic characteristics of respondents, injuries and illnesses they experience, their functional capacity, and the medical care they use. A specific diagnosis is recorded in the NHIS only if the respondent’s physician has provided one to the patient or if the symptoms reported by the respondent lead to an unambiguous diagnosis. For example, if a respondent reports a type of arthritis that has not been diagnosed by a physician and the symptoms do not clearly imply a discrete entity, the condition would be classified as “arthritis unspecified.” We selected all persons from the NHIS with an International Classification of Diseases (ICDA) (10) code for each of the 4 specific conditions in the study, eliminating persons with musculoskeletal comorbidities. In total there were 238 persons with R A (ICDA codes 7122-7125), 152 persons with OA (ICDA codes 7130-7139), 1,452with LBP (ICDA codes 7250-7259), and 2,284with TEN (ICDA codes 7310-7319). These numbers may not reflect the true prevalence of these conditions since persons with mild conditions may not have received a discrete diagnosis. Accordingly, studies of the NHIS indicate that respondent reports of diagnoses are generally specific, though not highly sensitive (1 1). We compared the relative impacts of each of the 4 discrete conditions among themselves, and with a sample of 300 persons drawn randomly from among all 18,690persons in the NHIS who had any musculoskeletal condition, regardless of discrete diagnosis. We also drew a random sample of 296 persons from among all 113,OOO respondents to the NHIS, to represent the entire U.S. population. This was ageadjusted to the sample of persons with any musculoskeletal condition. Most studies of persons with musculoskeletal diseases draw samples from clinical settings such as university medical centers or private practices. These studies provide valuable detail that is often unattainable in community-based surveys, particularly data on the severity of a condition. However, they generally obtain a relatively homogeneous sample group in terms of diagnosis, severity of illness, and demographic characteristics. One important attribute of the NHIS is that it generates respondents from the community. For this particular study, the community-based samples provide a more reliable estimate of the range of impacts of these 4 musculoskeletal conditions, among persons who are aware of their condition, both in terms of restriction of activities and medical care utilization. The NHIS reports the mean number of physician visits and hospitalizations and the extent of restricted activity for persons in each sample, stratified by demographic characteristics. When the measures of impact were continuous (number of physician visits, hospitalizations, and restricted activity days), we used an analysis of variance to determine if utilization or restriction of activities differed by sample and demographic (sex, race, age, and marital) characteristics. When the measures were categorical (kinds of activity limitations), we used chi-square tests for the same purpose. All reported comparisons among the particular samples in each analysis were significant ( P < 0.05) by the Ftest and chi-square. The statistical tests used assume inde- Table 1. Characteristics of persons in each sample studied Characteristics Fernalehale Whitelnonwhite Age (mean 2 SD) Marital status Married Widowed, separated, divorced Never married Usual activity Working Retiredlhealth Retiredlot her Housework Student Miscellaneous Rheumatoid arthritis (n = 238) Osteoarthritis (n = 152) Lower back pain (n = 1.452) Tendinitis (n = 2.284) All musculoskeletal conditions (n = 300) 65/35* 9317 54 2 16 68/32 9713 57 2 14 44/56 9317 48 2 14 58/42 9515 47 t 15 62/38 90110 54 2 17 60140 9218 54 t 19 69 23 6 62 33 5 74 19 71 19 7 7 64 24 9 66 21 13 29 12 4 43 3 9 26 13 6 48 0 7 53 6 4 28 8 4 44 5 6 39 3 2 39 5 1 53 3 5 32 3 * All numbers shown, except age, are percents. Sample of all U.S. citizens (n = 296) 8 36 7 4 903 IMPACT OF MUSCULOSKELETAL CONDITIONS pendence of the samples, because of the very slight representation of the discrete illnesses in the 2 control samples. Medical symptoms due to each condition, % Table 2. Rheumatoid arthritis Osteoarthritis Lower back pain Tendinitis Frequency of symptoms due to this condition Always Infrequently or never 54 28 44 37 25 55 11 77 Extent of symptoms due to this condition Great deal Little or none 64 7 50 I5 47 14 36 22 RESULTS Table 1 provides a broad outline of the social and demographic characteristics of the persons in each of the 6 samples in our study. The sex differential in the RA and OA groups reflects epidemiologic findings that women are more likely to have rheumatoid arthritis and osteoarthritis than men. The tendinitis and lower back pain samples also reflect epidemiologic reports on the sex distribution of these illnesses (12). The epidemiology literature reports that the prevalence rates of OA are similar among blacks and whites, but that blacks have much higher rates of RA than whites (13). In our study samples, however, there are fewer minorities reporting these conditions than would be expected. Nonwhites may be less likely to receive a specific diagnosis from a physician, and therefore less likely to be included in the disease-specific samples under review. Several studies have found that there is a higher probability of marital dissolution among the chronically ill than in the general population, and that this is independent of age (14, IS). Unfortunately the NHIS did not ask respondents to relate divorce or separation to illness, and it is therefore impossible to infer such relationships from this survey. We can only hypothesize that both age and illness are linked with the variation in marital status in the 6 samples in the study. Table 1 also shows the percentage of persons in each category who were working, doing housework, retired due to health reasons, or retired for other reasons. The TEN and LBP samples had the highest proportions of persons who were working (53%), while RA and OA had the lowest (29% and 26%, respectively). A large percentage of persons with RA and OA were doing housework (43% and 48%). These findings probably reflect the age and sex distribution of the diseases. However, they also reflect the impact of RA and OA in comparison with TEN and LBP. Table 2 reports the frequency and extent of symptoms experienced by persons with each of the 4 conditions under study. A much higher percentage of persons with RA (54%) claimed that their condition was always symptomatic than did those with the other 3 conditions; only about one-fourth of persons with RA stated that the symptoms never or only infrequently bothered them. The symptoms of tendinitis were the most episodic among the 4 conditions, with only 11% of those afflicted by the condition claiming that the condition always bothered them. Persons with RA were also more likely to report more extensive symptoms: 64% of those with RA stated that their illness Table 3. Utilization of physician and hospital services, by sample population Utilization Due to condition studied Physician visits in past year (mean rt SD) Interval since last visit (mean) % ever hospitalized % ever with surgery For all conditions Physician visits in past year (mean ? SD) Physician visits in past 2 weeks (mean 2 SD) Hospitalizations in past year (mean 2 SD) Rheumatoid arthritis Osteoarthritis Lower back pain Tendinitis 7.1 t 12.5 3.5 -+ 5.5 2.8 t 6.9 1.5 t 3.7 6-12 months 6-12 months 1 year I year 36 14 32 17 50 22 6 4 All musculoskeletal conditions Sample of all U . S . citizens 6.0 2 9.3 6.5 t 30.4 15.5 10.9 f 18.0 8.3 f 24.1 0.42 2 0.78 0.47 t 0.84 0.35 ? 0.87 0.3s -C 0.83 0.27 0.64 0.22 t 0.53 0.33 0.28 0.35 f 0.70 0.21 0.24 2 0.54 0.20 t 0.55 11.5 f ? 0.61 f 0.60 6.5 _t -C 13.0 0.57 -t KRAMER ET AL Table 4. Social and work limitations, by sample population Limitations Can't do usual activity (%) Limited in arnount/kind of major activity (%) Limited in activities outside major one (%) Not limited (%) This condition is primary cause of activity limitation (%) Persons wirh history of labor force participation, reporting work disability (%) Activity limitations in past 2 weeks 'due to this condition (mean) Restricted activity days Bed days Work loss days Activity limitations in past year due to this condition (mean) Bed days Work loss days Restriction of activities in past 2 weeks from all conditions (mean) Restricted activity days Bed days Work loss days Tendinitis All musculoskeletal conditions Sample of all U.S. citizens 13 7 9 8 39 36 19 31 14 12 24 14 30 13 8 66 12 38 49 8 70 52 51 41 3 24 29 6 2 10 6 2.2 0.3 1.7 0.8 0.3 1.2 0.4 0.3 0.3 0.1 0.0 22.9 7.4 14.2 5.2 8.3 8.0 1.1 3.4 1.6 0.2 2.2 I .o 0.3 2.3 0.8 0.5 I .7 0.5 0.2 1.1 0.4 0.1 Rheumatoid arthritis Osteoarthritis Lower back pain 22 18 43 1 .o bothered them a great deal, while only 7% reported little or no symptoms due to the condition. Again, tendinitis seemed to be the least symptomatic, with only 36% of these respondents claiming that this condition bothered them a great deal. Table 3 presents data on the differences in utilization of physician and hospital services for persons with RA, OA, 'TEN, LBP, any musculoskeletal condition, and for the age-adjusted sample of all U.S. citizens. Persons with RA clearly utilized outpatient physician services for their condition most frequently, while persons with LBP were hospitalized and had surgery for their condition most often. The mean number of visits in 1 year attributable to RA was 7.1 ; the corresponding figures were 3.5 for OA, 2.8 for LBP, and 1.5 for TEN. Considering that persons with LBP utilized outpatient physician services for their condition so infrequently and on average had not visited a physician for 1 year for their condition, it is surprising that these persons had such a high surgery and hospitalization rate. This is even more striking considering that over half the persons with LBP reported experiencing 1.2 1.5 0.5 0.2 their symptoms infrequently (Table 2). Nevertheless, 50% of the persons interviewed claimed that they had been hospitalized at some time for their condition, compared with 36%, 32%, and 6% for RA, OA, and TEN, respectively. Additionally, 22% of persons with LBP in the survey had had surgery for their condition, compared with 14%, 17%, and 4% for RA, OA, and TEN, respectively. The mean number of physician visits in a year for all reasons ranged from 6.5 for persons with TEN to 11.5 for those with RA, Among persons with any musculoskeletal condition, the average number of physician visits in a year was 6.0. The corresponding figure in the age-adjusted sample of the U.S. population as a whole was 6.5, indicating that overall utilization of physician visits among all persons with musculoskeletal disease is similar to that of persons in the same age range who do not necessarily have musculoskeletal disease. The difference between the mean numbers of visits attributed to the specific condition and to all conditions provides a rough indication of the comorbid utilization of persons with each of the 4 conditions 905 IMPACT OF MUSCULOSKELETAL CONDITIONS under study. The typical person with RA visited the physician almost 4% times a year for reasons other than the RA (11.5-7.1 visits); the corresponding figures for persons with OA, LBP, and TEN were 7% ~ Y z and , 5 , respectively. Thus, persons with these conditions make almost as many visits to the physician for reasons other than their musculoskeletal condition as a similarly aged U.S. citizen makes for all reasons, another indication that persons with these specific conditions use a large quantity of medical services. In fact, persons with each of the 4 conditions under study reported having an average of 1 other medical condition (data not reported). Table 4 reports on activity limitations experienced by the persons in each sample. From the data it is apparent that rheumatoid arthritis caused more severe restrictions in activities than the other illnesses. Twenty-two percent of the persons in the RA sample reported that they were unable to perform their usual activity, while only 24% were not limited in activities in any way. These figures compare most strikingly with those for persons with TEN, only 7% of whom reported that they were unable to perform their usual major activity, and 66% of whom were not limited in any way by their illness. Osteoarthritis and lower back pain followed RA in terms of effect on activity limitation. About half of all persons with any musculoskeletal condition reported being limited by their illnesses to some extent. In contrast, only 30% of the ageadjusted sample of all U.S. citizens claimed to be limited in activities. At least 40% of all persons with a musculoskeletal condition experienced some limitation in their major activity, a percentage about twice as high as that for the age-adjusted sample of all U.S. citizens. Musculoskeletal disability was the primary cause of limitation for the majority of persons with RA and OA who experienced limitations. In comparison, only 3% of the persons with tendinitis who experi- Table 5. enced limitations reported that this illness was the primary cause of their limitation. One particularly striking finding was that at least one-foutth of persons with RA or OA who had held jobs at some time in the past reported that they were retired due to health reasons. In contrast, only 6% of those with LBP reported work disability. Moreover, 10% of the persons in the all musculoskeletal disease sample with a work history reported work disability. The age-adjusted U.S. sample experienced significantly less work disability (6%). RA generated the most severe impacts as reflected in the number of restricted activity and bed days attributable to the condition. For example, the mean number of bed days due to the condition in the past year was 22.9 for RA, 14.2 for OA, 8.3 for LBP, and 1.1 for TEN. DISCUSSION Previous studies (1-8) have indicated that musculoskeletal conditions are among the leading diseases associated with social and economic costs to individuals and society. In fact, they show that musculoskeletal diseases surpass almost all other disease groups in measures of disability, restriction of activity, use of vocational rehabilitation, and medical costs. The only area in which they do not have a comparatively high impact rate is as a cause of death. However, these findings are derived from clinical samples or from aggregate-level data. The use of a community-based sample of individuals has enabled us to obtain a more accurate estimate of the impacts of 4 musculoskeletal conditions-rheumatoid arthritis, osteoarthritis, tendinitis, and lower back pain-than is possible from a clinical study or from aggregate data. We found that persons with RA utilize significantly more physician services than persons with any of the other musculoskeletal National impact of rheumatoid arthritis (RA) and osteoarthritis (OA)* Illness and estimated prevalence (reference) Physician visits due to this condition in 1 year (millions) All physician visits for persons with this condition in I year (millions) Hospitalizations of persons with this condition in 1 year (millions) Bed days due to this condition in 1 year (millions) Work loss days due to this condition in I year (millions) RA 0.2% (13) 2. I 3.5 0.1 6.9 2.2 45.1 142.2 3.7 185.3 67.9 OA 8.7% (18) ~ * Based on U.S. population of 150 million adults aged 18-79 in 1980, and published prevalence rates of RA and OA. 906 conditions under study. Persons with rheumatoid arthritis also experience the most extensive limitation in activities, although the impact of osteoarthritis on functional ability is also severe. Persons with lower back pain use more hospital services and receive more surgery than persons with any of the other conditions under study. Tendinitis is, as expected, the least severe of the 4 musculoskeletal conditions as assessed by utilization and restriction of activity measures. It is valuable to consider all musculoskeletal conditions together when comparing them with, for example, respiratory diseases. The value of grouping all musculoskeletal conditions together, however, is limited when one wants to deal with a particular one. There are a number of reasons it is important to study musculoskeletal conditions individually. First, the needs of persons with particular conditions are different depending upon the type and seventy of the condition. Second, the National Institutes of Health allocates funds on the basis of the demonstrated importance of illnesses, using as criteria the number of persons affected, extent and severity of impact, and direct and indirect costs (16). Third, Health Systems Agencies, the federally funded, local health planning agencies, use data on impacts of specific diseases for resource allocation purposes (17). The wide variation in impact of disease and utilization of medical services among the 4 musculoskeletal conditions demonstrates the importance of considering each one separately, for health planning purposes. This becomes even clearer when we compare the sample representing persons with all musculoskeletal conditions with the age-adjusted sample of persons in the United States. The similarity between these 2 groups in terms of health care used reveals that in regard to medical care used, most persons with musculoskeletal diseases broadly defined are not significantly different from similarly aged persons who do not have musculoskeletal disease. Health planning and resource allocation based on the premise that most persons with musculoskeletal conditions are similar to the age-adjusted U.S. sample would inadequately reflect the resource requirements €or specific types of musculoskeletal illnesses. It would lead to an underallocation of resources for the more severe illnesses such as RA and OA, and an overallocation for others such as TEN. When allocating resources, health planners can use information from studies such as this one to take into account the special medical and social service needs of persons with specific conditions. Table 5 KRAMER E T AL provides an example of how health planners might use such information for RA and OA. The table shows estimates of several dimensions of the national impact of RA and OA, using conservative estimates of the prevalence of these 2 illnesses among adults in the United States and estimates of disease impact from Tables 3 and 4. Using only the strictest definitions of these conditions and the most conservative estimates of prevalence, RA and OA are responsible for 2 and 46 million physician visits per year, respectively, and result in 2 and 68 million work loss days, respectively. The aggregate impacts of these 2 conditions will increase significantly because the prevalence of each and incidence of OA increase with age. The present study demonstrates the wide range in disability, restriction of activity, and medical care utilization among 4 musculoskeletal conditions: rheumatoid arthritis, osteoarthritis, tendinitis, and lower back pain. Our study also reveals significant differences in utilization and impacts between the individual musculoskeletal conditions and a sample representing all musculoskeletal conditions. Moreover, the present study demonstrates that persons with a broad range of musculoskeletal conditions are similar to persons of similar age in terms of medical care use, although they experience higher rates of disability. We conclude that planning on the basis of musculoskeletal diseases as a whole would not serve the specific and different needs of those with these 4 discrete conditions. ACKNOWLEDGMENTS The authors gratefully acknowledge the wise counsel of Michael Nevitt and Curtis Henke, and the assistance of Roy Kriedeman. REFERENCES Acute Conditions: Incidence and Associated Disability, US, 1974-1975. Vital and Health Statistics Series 10, Number 114. USDHEW Publication no. (HRA)77-1541, 1977 Lehman JF: Patient care needs as a basis for development of objectives of physical medicine and rehabilitation teaching in undergraduate medical schools. J Chronic Dis 21:3-12, 1968 Inpatient Utilization of Short-Stay Hospitals, by Diagnosis, US, 1971. Vital and Health Statistics Series 13, Number 16. USDHEW Publication no. (HRA)75-1767, 1975 Physician Visits: Volume and Interval Since Last Visit, US, 1971. Vital and Health Statistics Series 10, Number 97. USDHEW Publication no. (HRA)75-1524, 1975 IMPACT OF MUSCULOSKELETAL CONDITIONS 5 . Kelsey J, Pastides H , Bisbee G. Musculo-Skeletal Disorders: Their Frequency of Occurrence and Their Impact on the Population of the United States. New York, Prodist, 1978 6. Yelin E, Meenan R, Nevitt M, Epstein W: Work disability in rheumatoid arthritis: effects of disease, social, and work factors. Ann Intern Med 9331-556, 1980 7. Meenan RF, Yelin EH, Nevitt M, Epstein WV: The impact of chronic disease: a sociomedical profile of rheumatoid arthritis. Arthritis Rheum 24544-549, 1981 8. Lubeck DP, Spitz PW, Fries JF: The Health Assessment Questionnaire (HAQ): assessment of personal economic costs (abstract). Arthritis Rheum (suppl) 25:S149, 1982 9. Current Estimates from the Health Interview Survey, United States, 1976. Vital and Health Statistics Series 10, Number 119. USD-HEW Publication No. (PHS) 781547, 1977 10. Eighth Revision International Classification of Diseases. USD-HEW Publication No. (PHS) 1693, 1977 11. Health Interview Responses Compared with Medical 12. 13. 14. 15. 16. 17. 18. 907 Records. Vital and Health Statistics Series 2, Number 7. USDHEW Publication no. (PHS) IOOO, 1965 Cobb S: The Frequency of the Rheumatic Diseases. Cambridge, Harvard University Press, 1971 Rheumatoid Arthritis in Adults, US, 1960-1962. Vital and Health Statistics Series 11, Number 17. Public Health Service Publication no. 1000, 1966 Medsger A , Robinson H: Comparative study of divorce in rheumatoid arthritics and other rheumatic diseases. J Chronic Dis 25:269-275, 1972 Franklin P: Impact of disability on the family structure. SOCSecur Bull 5:3-18. 1977 Strickland S: Research and the Health of Americans. Lexington, Massachusetts, Lexington Press, 1978 Knox E, Acheson R, Anderson D, Bice T, White K: Epidemiology in Health Care Planning. Oxford, England, Oxford University Press, 1979 Prevalence of Osteoarthritis in Adults by Age, Sex, Race, and Geographic Area, United States, 1960-1962. Vital and Health Statistics Series 11, Number 15. USDHEW Publication no. (PHS)1000, 1966 Curriculum in Rheumatology for Office Nurses August 7-10, 1983, Westowner in Madison, Wisconsin, sponsored by the Multipurpose Arthritis Center at the Dartmouth-Hitchcock Medical Center, with faculty from both Dartmouth College and from the Jackson Clinic in Madison. Topics to be covered include communications, biology and pathophysiology of the joint, joint examination, musculoskeletal symptoms and treatment of rheumatic diseases, and strategies of patient education. Application will be made to the New Hampshire Nurses Association for appropriate CEUs. For further information, contact Martha Doolittle, Dartmouth-Hitchcock Arthritis Center, Hanover, NH 03756.