Arthritis and related musculoskeletal diseases are the most common chronic conditions among older adults in the United States (Lawrence et al., 1989; Scott and Hochberg, 1993). These diseases are strongly associated with the presence of functional limitations, disability, and reduced quality of life in this segment of the population (Badley, 1995; Ettinger et al., 1994; Guccione et al., 1994; Hughes et al., 1993; Jette et al., 1990; Stewart et al., 1989; Verbrugge et al., 1991).
This chapter describes the prevalence of common arthritic and other musculoskeletal diseases and the symptoms of these conditions, as reported by participants in the Women's Health and Aging Study (WHAS). The prevalence of physical signs of arthritis noted on an examination performed by a trained nurse and the results of lower extremity muscle strength testing are also described. Finally, prevalence estimates are examined in relation to both age and the level of disability.
Table 12.1 reports the prevalence of arthritis, defined as a positive response to the question "Has a doctor ever told you that you had arthritis?" Three-quarters of disabled women age 65 years and older reported being diagnosed with arthritis by a doctor; prevalence did not vary with age. Prevalence of physician-diagnosed arthritis was, however, slightly more common in women with difficulty in activities of daily living (ADLs) than in moderately disabled women.
As expected, the most commonly reported type of arthritis was osteoarthritis; however, the majority of women with self-reported physician-diagnosed arthritis did not know what type of arthritis they had. About 12 percent of these women reported rheumatoid arthritis; the prevalence of definite rheumatoid arthritis in women age 65 to 79 years in the United States was estimated as 5 percent (Lawrence et al., 1989). Reported rheumatoid arthritis was most common in women who received help in performing ADLs and least common in women with moderate disability.
Table 12.1 also gives information on current treatment for arthritis. The denominator for the percentages in this table is the total number of women in each age or disability category, not just those who reported a physician diagnosis of arthritis. Reported current treatment for arthritis was slightly higher among women with ADL difficulty than in those with moderate disability. Overall, less than 9 percent of women reported having surgery for treatment of arthritis; the majority of these women had surgery on their knees. Joint surgery in general, and hip and knee surgery specifically, were more commonly reported by women having difficulty with ADLs than by women with moderate disability but no ADL difficulty.
The prevalence of other osteoarticular conditions is presented in Table 12.2. Sixteen percent of women reported having been told by a doctor they had osteoporosis; however, only one-third of these women reported current treatment for osteoporosis. The prevalence of reported osteoporosis was highest among women age 75 to 84 years, and the proportion of those with osteoporosis reporting current treatment was lowest in those age 85 years and older.
Table 12.2 also shows the prevalence of reported fractures. Six percent of the women reported hip fracture. The prevalence increased with age, with 15 percent of women age 85 years and older reporting a hip fracture. Women with ADL difficulty, especially those who received help, were more likely to report having had a hip fracture than those with only moderate disability. Fractures of other bones, particularly the wrist or arm, were very common in these women. Overall, one-third of women reported one or more fractures; the prevalence in women age 75 years and older was approximately 40 percent. Women with ADL difficulty were more likely to report a prior fracture than women with only moderate disability. About one-fifth of women reported a history of disc disease or spinal stenosis. Of these women, only 5 percent reported surgical treatment. The prevalence of reported disc disease or spinal stenosis was greater in women with ADL difficulty than in those with only moderate disability.
The prevalence of reported pain ". . . on most days for at least one month . . ." in the hands or wrists, hips, knees, feet, and lower back during the past year by age and level of disability is shown in Table 12.3. The most common site of pain was the knees, followed by the lower back, feet, hands or wrists, and hips. Over one-half of women had pain or stiffness in the hands or wrists and in the knees in the past month, and about 40 percent of women had pain in the hips and in the feet during the previous month. The prevalence of reported pain at each site, during both the past year and the month before the interview, was lower in women age 85 years and older than in younger women and higher among women who reported difficulty with ADLs compared with those with only moderate disability.
The level of severity of self-reported pain in the hands or wrists, feet, and back is given in Table 12.4. These data come from participant report of pain using visual analog scales that range from 0 to 10, representing mild (0-3), moderate (4-6), or severe pain (7-10). The scales were presented only to women who stated that they had pain during the month before the interview. Of those with pain, the majority, independent of age and level of disability, had moderate or severe pain. The level of severity of self-reported pain in the knees or hips is given in Table 12.5. These data are based on answers to five pain questions taken from the Western Ontario McMaster Osteoarthritis Index (Bellamy et al., 1988); level of pain is categorized as mild (0-3), moderate (4-6), or severe (7-10) in those who stated that they had pain during both the past year and the month before the interview in their hips and/or their knees. The majority of women who reported current pain in their hips and/or knees had moderate or severe pain when walking on a flat surface, going up and down stairs, and standing upright; however, less than half had moderate or severe pain when sitting or lying down or in bed at night. The proportion of those with current pain who reported moderate or severe pain did not appear to vary with age or level of disability. Of note, however, was the higher proportion of women in the oldest age group and in the group that required help performing ADLs who reported that they did not stand upright, walk on a flat surface, or go up and down stairs. Avoidance of or inability to perform these tasks may lead to an underestimate of the prevalence of and level of severity of complaints of large joint arthritis associated with these weight-bearing activities.
Morning stiffness and swelling with tenderness of the joints were reported less often than joint pain at all sites (Table 12.3). The prevalence of morning stiffness was higher than that of swelling in both the hands or wrists and knees, but not in the feet. This may be attributable to some confusion between dependent edema and joint swelling by some of these women. Both age-specific and disability level-specific patterns of prevalence of morning stiffness and swelling were similar to those for reported pain.
Trained nurses performed a standardized examination of the participants' peripheral joints. The wrists and metacarpophalangeal and proximal interphalangeal joints of the hands were examined for tenderness on palpation and pain on motion, soft tissue swelling, and limited range of motion; the distal interphalangeal joints of the hands were examined for tenderness on palpation and pain on motion, bony enlargement, and limited range of motion; the hips were examined for pain on motion; the knees were examined for tenderness on palpation and pain on motion, bony enlargement, crepitus, and angular (varus or valgus) deformity; the feet were examined for the presence of bunions and hammer toes; and functional shoulder rotation was assessed.
Table 12.6 presents the prevalence of abnormalities found on physical examination. The most commonly involved joint group was the knees. Over 80 percent of women had patello-femoral crepitus on flexion and extension of their knees; this sign is the most common physical finding in patients with osteoarthritis of the knee and is one of the clinical features utilized in classifying cases of knee osteoarthritis (Altman et al., 1986). Approximately 35 percent of women had tenderness or pain on motion, 42 percent had bony enlargement of the knees, and 17 percent had either a valgus or varus deformity of the knee. These findings were more common in women with ADL difficulty, especially those needing help with ADLs, than in women with moderate disability. The prevalence of both bony enlargement and angular deformities increased with age in these women.
Abnormalities were found in the feet and hands or wrists in a majority of women. About 70 percent had bunions and 50 percent had hammer toes. The prevalence of both bunions and hammer toes increased with age; hammer toes were slightly more common in women with ADL difficulty than in women with moderate disability. Tenderness on palpation or pain on motion and limitation of joint range of motion in the hands or wrists were present in the majority of women and were slightly more common in women with ADL difficulty than in women with moderate disability. Swelling in the joints of the hands or wrists was present in about one-quarter of women and was found in a higher proportion of women with ADL difficulty than in women with moderate disability.
Almost two-thirds of women were fully capable of functional shoulder rotation; the proportion able to perform this maneuver, however, declined with increasing age and was markedly lower in women who received help with ADLs than in women with only moderate disability. More detailed results of the shoulder rotation assessment are presented in Chapter 4, Table 4.9. Pain on motion of the hips was present in only one-quarter of women and was not related to either age or level of disability.
Knee extensor (quadriceps) muscle strength and hip flexor (iliopsoas) muscle strength were determined using a Nicholas Manual Muscle Tester (Model # BK-7454, Fred Sammons, Inc., Burr Ridge, IL), a hand-held dynamometer that measures the peak force required to break an isometric contraction as the examiner applies force against the subject. Tests were conducted with the participant seated comfortably in a hard chair. The dynamometer was placed a few inches above the right ankle between the medial and lateral malleolus for the knee extension test and immediately proximal to the femoral condyles at the distal thigh for the hip flexion test. Participants were instructed to push against the dynamometer as hard as they could, and the examiner then pushed hard enough to break the contraction.
Results of functional tests of lower extremity muscle strength are shown in Table 12.7; results of tests of upper extremity muscle strength are given in Chapter 4, Tables 4.6 through 4.8. Over three-quarters of these elderly, disabled women were able to complete tests of hip flexor and knee extensor muscle strength; however, the proportion able to perform the tests declined with increasing age and was lower among those with ADL difficulty, particularly among those receiving help with ADLs, than among those with moderate disability.
Among those who completed testing, the mean and median values for both hip flexor strength and knee extensor strength declined with increasing age and were higher among those with moderate disability than women who received help with ADLs. These data support the validity of functional testing performed in the home by trained nurses on older, disabled women.
As expected, arthritis was the most common condition reported by women in the WHAS. It affected multiple joints and frequently caused knee pain which was most severe going up and down steps. Physical examination confirmed the frequent knee involvement and also clarified the other joints affected. Most often arthritis was managed with medications, although a small proportion had surgical treatment. Symptoms and examination findings in older women with disability provide insight into the relationship of musculoskeletal disease with severity of disability.
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