Extent of occupational hand use among persons with rheumatoid arthritis

Authors


Abstract

Objective

Occupational hand use is increasing due to increased computer use and could place persons with rheumatoid arthritis (RA) at risk for work disability. Although hand involvement in RA is typical, there is little information about occupational hand use in relation to RA. Study objectives were to describe the extent of occupational hand use by persons with RA; the types of jobs that require extensive hand use; the relationship between occupational hand use and joint pain; and the extent of occupational hand use among persons with shorter versus longer disease duration.

Methods

Cross-sectional survey data from 2,761 employed participants with RA from a US national cohort were used. Extent of occupational hand use was measured by the hand-use item from a job physical demand scale used in prior RA studies. Analyses included descriptive statistics and chi-square tests.

Results

The mean age was 50.6 years, 78.5% were women, 91.8% were white, and 68.8% had more than a high school education. Eighty-three percent of participants reported extensive occupational hand use. Large portions of participants in all types of jobs reported extensive hand use, 92% with administrative support jobs and 69% with operator/laborer jobs. Participants with extensive occupational hand use were more likely to have hand joint pain than those with moderate hand use (66% versus 58%; P = 0.004). Extensive hand use did not vary by disease duration (83% and 84% in participants with ≤15 and >15 years' duration, respectively).

Conclusion

Extensive occupational hand use was ubiquitous among employed persons with RA and was associated with greater hand pain.

INTRODUCTION

Work disability is a major burden of rheumatoid arthritis (RA) (1, 2). Having a job with a high level of physical demand has been a primary predictor of RA work disability (1, 2), but in recent years the overall physical demand of jobs in the US has been decreasing (3). This could benefit persons with RA; however, one aspect of job physical demand, hand use, may be increasing in relation to the increased use of computers at work. In 2001, 54% of all US workers used a computer at work, up from 38% in 1989 (4, 5). Women are especially likely to use computers at work, with 60% of them doing so in 2001 (5). Because of the high frequency of hand involvement in RA, increasing occupational hand use could offset any benefit from the lessening of overall job physical demand.

Although occupational hand use has the potential to be an important risk factor for RA work disability, few studies have examined the issue. Studies to date suggest that occupational hand use is often a problem for employed persons with RA, but only small, select samples have been used in these studies (6–9). We wished to expand the information available about occupational hand use in persons with RA, and so we used data from a large, national sample of persons with RA to describe the following: the extent of occupational hand use in comparison with the demand of other types of physical job actions, the types of jobs requiring extensive hand use, the relationship between occupational hand use and joint pain, and the extent of occupational hand use among persons with shorter versus longer disease duration.

SUBJECTS AND METHODS

Data used in this study were from participants in the National Data Bank (NDB) longitudinal study of RA outcomes, a large dynamic cohort of patients with rheumatologist-diagnosed RA. Patients are periodically recruited to the cohort from practices of US rheumatologists or pharmaceutical company–sponsored registries. NDB participants are surveyed semiannually, at which times they are asked to fill out detailed questionnaires by mail or online. Approximately 8% of participants decline to fill out the questionnaires per year. Data from employed participants in the first of either of the two 6-month data collection periods in 2002 (January to June or July to December) were used in this cross-sectional study.

NDB participants have always been queried about employment, but more extensive employment questions, including items about the physical demand of jobs and type of job, were added to the questionnaires beginning in 2002. All currently employed participants were instructed to answer these questions. The sample was limited to participants who were currently employed and were between 18 and 64 years of age; employment was defined as it is in the Current Population Survey, i.e., any paid work, self-employment work, or at least 15 hours per week of nonsalaried work for a company or farm owned by the participant's family.

Measures.

Occupational hand use and other physical demands of participants' jobs were assessed using the job physical demand scale from the 1978 Social Security Administration Study of Disabled and Nondisabled Adults (10, 11). This scale assesses the extent to which 12 physical actions are performed at work. To reduce respondent burden, we excluded 4 less relevant actions, 2 eye-use actions and the light and heavy lifting/carrying weight actions. The 8 actions assessed in this study were as follows: using fingers/hands to grasp, handle, write, use keyboards, etc; sitting for long periods; walking; using stairs or inclines; standing for long periods; stooping, crouching, or kneeling; reaching; and lifting or carrying weights up to 25 pounds. The hand-use item in the original scale was listed as “use fingers to grasp or handle.” Because this did not clearly include actions such as writing and keyboard use, we expanded the description of this item. Participants reported the extent to which each job action was performed using the same 3 categories of response used in the original scale, i.e., “none or very little” (scored as 0), “some” (scored as 1), and “a lot” (scored as 2). We defined extensive job action use or demand as “a lot.”

Study participants reported the type of their main job using a checklist of 7 types of jobs. Six of the job types were derived from the 1990 US Census Bureau's 5 main occupation classification categories (12). Because 1 of the 5 categories, technical, sales, and administrative support jobs, covered a large number of the jobs that we expected participants to have and is commonly divided in other job classification schemes, we split this category into 2 job types, technical and sales jobs and administrative support jobs. Each of the 6 main types of jobs (e.g., managerial or professional jobs) was followed by a list of 8–14 examples of specific job titles (e.g., registered nurse) that were taken from lists of job titles under each 1990 US Census Bureau main occupation category. The 6 main types of jobs were as follows: managerial/professional, technical/sales, administrative support, service, precision production/craft/repair, and operator/fabricator/laborer. In addition, we added a seventh job type of “other,” along with space to write in another type of job. We used the written description to assign “other” jobs to the closest job type.

Pretesting was conducted to determine whether individuals could accurately categorize their job by the job types in our classification scheme. Participants in a recently completed employment study were recontacted and asked whether their main job had changed since last contact and to classify their job using the 7 job types. The type of jobs these individuals had in the prior study had been elicited by telephone using detailed questions about job title and main job duties. Of 47 individuals who responded and had not changed jobs, 46 classified their jobs into the same job type as we had.

Participants rated their pain or tenderness in each joint or group of joints (e.g., hand knuckles) over the past week on a 4-point scale, where 0 = none, 1 = mild, 2 = moderate, and 3 = severe pain; previous studies had shown that such patient self reports are valid (13). Joints on both the right and left side of the body were asked about separately, but scores for both sides were combined to obtain an average score for each pair or group of joints. Because RA tends to be bilateral, few subjects had scores of 0.5, 1.5, and 2.5. Therefore, we collapsed the 0.5 scores into a score of 1, the 1.5 scores into a score of 2, and 2.5 into a score of 3.

Data from the Health Assessment Questionnaire (HAQ) Disability Index were used to describe the extent of subjects' functional limitation. The HAQ is a self-report instrument with established reliability and validity for arthritis samples that measures 8 areas of function (14). All 20 HAQ questions were included in both 6-month NDB surveys.

Statistical analysis.

The sample was described by age, sex, race, education, disease duration, and functional limitation. To describe the extent of occupational hand use in comparison with the demand required for the other types of physical job actions, frequencies of the 3 demand response categories were calculated for each of the 8 actions. To describe the types of jobs requiring the most extensive hand use, we calculated frequencies of the finger/hand demand response categories for participants in each of the 6 types of jobs.

The frequencies of the pain/tenderness levels for each of the joint pairs or groups were examined; joints included the proximal interphalangeal (PIP), metacarpophalangeal (MCP), wrist, elbow, shoulder, hip, knee, ankle, metatarsophalangeal, and neck joints. Because for each joint pair or group substantial portions of participants reported no pain (e.g., 65% elbow and 35% PIP joints), we then dichotomized the pain categories into pain present (mild, moderate, and severe pain combined) or absent before examining the association between pain and hand use. For each of the PIP, MCP, and wrist joints, a 2 × 3 table was created with the dichotomized pain and occupational hand use variables. Chi-square tests were conducted to determine if differences were significant.

To describe the extent of hand use, and the other job actions, among subjects with shorter versus longer disease duration, we first created disease duration subgroups. The subgroups were classified in 3-year segments of disease duration up to 15 years; the last subgroup was >15 years' duration, which we considered to be long-standing disease. Then for each job action, we observed the proportions of participants in each duration subgroup, arranged sequentially, with extensive demand. With the exception of the finger/hand use action, changes in the proportions of subjects with extensive demand in all of the other job actions were observed in the long-standing disease subgroup. Therefore, we dichotomized disease duration into ≤15 years and >15 years categories. Then for each job action, a chi-square analysis was conducted to examine the difference in extensive demand between participants with long-standing disease and those with shorter disease duration.

RESULTS

In the 2002 NDB data, 3,001 participants were employed and were 18–64 years old. Of these, 240 did not supply information about occupational hand use (92% response rate), so the sample consisted of 2,761 individuals. The mean age was 50.6 years (range 20–64 years), 78.5% were women, 91.8% were white, 68.8% had an education beyond high school, and 43.3% had managerial or professional types of jobs (Table 1). These individuals had had RA for a mean ± SD of 12.3 ± 8.9 years, and their mean ± SD functional limitation level (HAQ) was in the mild range (0.79 ± 0.6). The participants who did not supply occupational hand use data were similar to those who did except that they were slightly younger, had a mean age of 47.8 versus 50.6 years (P = 0.02), and were more likely to have professional or managerial jobs (55% versus 43%; P = 0.009).

Table 1. Sample characteristics (n = 2,761)
CharacteristicValue
  • *

    HAQ = Health Assessment Questionnaire. Score range 0–3, 0 = no limitation.

Age, mean (range) years50.6 (20–64)
Female sex, %78.5
White race, %91.8
Education beyond high school, %68.8
Managerial or professional jobs, %43.3
Disease duration, mean ± SD years12.3 ± 8.9
Functional limitation, mean ± SD HAQ score*0.79 ± 0.6

Of all the job actions assessed, the extent of demand for finger/hand use (occupational hand use) far exceeded that of any other action (Table 2). Eighty-three percent of participants reported performing finger/hand actions “a lot” at work, whereas the next most extensively performed action, sitting for long periods at work, was performed “a lot” by 43% of participants.

Table 2. Extent physical job actions are performed at work*
Job actionNone/littleSomeA lot
  • *

    Values are the percentage.

Use fingers/hands2.114.783.2
Sit long periods20.936.542.6
Walk135235
Use stairs45.644.010.4
Stand long periods39.931.828.3
Stoop/crouch/kneel51.838.59.7
Reach30.15217.6
Lift/carry weights ≤25 pounds59.429.611.1

The extent of occupational hand use was high in all types of jobs (Table 3). Not surprisingly, 91.7% of participants with administrative support jobs reported “a lot” of hand use. The rate of extensive hand use was lowest for participants with operator/facilitator/laborer jobs, but nearly 70% of these subjects reported “a lot” of hand use. We confirmed the job type findings by examining the extent of occupational hand use in participants with and without educational attainment beyond high school and found that 83% of both subgroups reported extensive hand use.

Table 3. Extent of occupational hand use by job type*
Job typeNone/littleSomeA lot
  • *

    Values are the percentage.

Managerial/professional1.515.383.2
Technical/sales2.416.081.6
Administrative support0.97.591.7
Service5.621.572.9
Precision production/craft/repair2.113.584.4
Operator/facilitator/laborer4.925.569.6

Joint pain was present and more severe in the hand joint sites than in any of the other joints. Approximately half of participants reported mild, moderate, or severe pain in each joint pair or group, but the proportions were highest for pain in the hand joints (65% PIP, 64% MCP, and 61% wrist joints) and lowest for elbow pain (35%). The proportions of participants with moderate or severe pain were also highest in the hand joints (29% PIP, 29% MCP, and 24% wrist joints), and the next highest proportion with this level of pain was for the neck (22%).

In each hand joint group, the pattern of the proportions of participants with pain (mild, moderate, or severe) in the 3 levels of occupational hand use was similar (Table 4). Proportions of participants with pain were highest in the “none or very little” hand use category, next highest in the “a lot” of hand use category, and lowest in the “some” hand use category. Chi-square test results of the relationship between pain in each of the PIP and MCP joint groups and the 3-level hand use variable were significant (P = 0.02 and P = 0.03, respectively). Because the number of participants with “none or very little” hand use was small (n = 57), we then confined the sample to those with “some” or “a lot” of pain and repeated the chi-square tests. The differences in the proportions of participants with pain in the PIP or MCP joints and “a lot” versus “some” hand use were also significant (P = 0.004 and P = 0.02, respectively).

Table 4. Association of occupational hand use with hand joint pain*
Joint groupNone/little (n = 57)Some (n = 397)A lot (n = 2,269)
  • *

    PIP = proximal interphalangeal; MCP = metacarpophalangeal.

  • Right and left joints combined.

  • P = 0.004.

  • §

    P = 0.02.

Percentage with pain in PIP joints66.758.465.8
Percentage with pain in MCP joints70.258.4§64.8§
Percentage with pain in wrist joints66.757.962.0

The percentages of participants who reported extensive hand use were similar across all disease duration subgroups (0–2 years: 82%; 3–5 years: 84%; 6–8 years: 84%; 9–11 years: 85%; 12–15 years: 80%; and >15 years: 84%). There was no difference in the proportions of participants with extensive occupational hand use in the long-standing or shorter disease duration subgroups (84% versus 83%; P = 0.69). For the sitting a long time job action, the proportion of participants with extensive demand increased with long-standing disease (from 41% to 48%; P = 0.0006), whereas for the remaining job actions, the proportions of subjects with extensive demand decreased somewhat with long-standing disease (e.g., walking decreased from 36% to 32%, P = 0.02 and lifting ≤25 pounds decreased from 12% to 8%, P = 0.0005).

DISCUSSION

Data on the extent of occupational hand use from our large, US national sample of employed persons with RA indicate that extensive on-the-job hand use is very common. Eighty-three percent of study participants reported using their fingers and/or hands a lot at work, which was nearly twice the extent of the next most commonly performed job action, sitting for a long time. Large portions of participants in all types of jobs, including those with managerial or professional jobs, reported extensive occupational hand use.

Given the frequency of hand involvement in RA, it might be assumed that extensive occupational hand use is problematic for employed persons with RA, and other findings from our study suggest that this is true. Subjects with “a lot” of hand use were significantly more likely to report having pain in the PIP and MCP joints than those with “some” hand use. However, although these results suggest a link between occupational hand use and hand pain, this could not be determined with certainty because of the cross-sectional design of the study. In addition, the reporting periods for the measures of hand use and joint pain were different; hand use was measured at the level of the job in general, whereas pain was reported over the past week.

We also found that similarly large portions of subjects with long-standing disease and shorter disease duration reported extensive occupational hand use. This finding could indicate that extensive occupational hand use is not as serious an impediment to employment than are actions such as walking, but an alternative explanation is that most jobs require extensive hand use, and thus extensive hand use is hard to avoid. The fact that extensive hand use was ubiquitous in all types of jobs further suggests that this is the case.

Most previous studies also suggest that occupational hand use is problematic for many persons with RA. In a sample of 20 employed women, hand function was scored as the worst of 5 types of work capacity functions, and better hand dexterity and greater grip strength predicted ability to perform medium-level work, as opposed to light work (6). Assessment of the work capacity of 26 persons with RA through typing and other manual tests indicated that the number of jobs these persons could perform was reduced from 11.5 million to 2.6 million (7). Typing and writing were among the most frequently reported work challenges reported by 25 women with RA in a descriptive study (8). In a study of work problems of employed persons with rheumatic diseases (9), the most common problem cited by the subgroup of individuals with RA was with “handling” activities; 45 (66%) of 68 individuals reported this type of problem (unpublished observation), and 49% reported that writing was a problem.

It is possible that many persons with RA find ways of accommodating hand activities at work. In a recent Canadian study, 61% of persons with osteoarthritis or RA had modified their hand use activities at work (15), and in a case example, a woman with RA managed to hold a senior clerical position that required typing in spite of marked hand deformities (16). Although the woman's typing speed was reduced, it was sufficient for her job.

There is very little information about the effect of occupational hand use on employment retention among persons with RA. In a national sample, Reisine et al found that the Dictionary of Occupational Titles job characteristic “complexity of working with things,” which suggests hand use, predicted job loss over 5 years (17). In contrast, no association between diminished hand function and indirect costs of sick leave and early retirement was found in a study of 77 persons with RA (18). However, many subjects were elderly and had no sick leave or retirement costs (19).

Few rehabilitation interventions have been developed for RA-related occupational hand use problems. Perhaps the most common recommendation is to use working splints, especially wrist splints. These splints may provide pain relief and generally do not reduce function (20, 21). Silver ring splints have been reported to improve dexterity in some persons with RA (22).

Another common recommendation is to change to a job that is less physically demanding, such as office work. However, as Minor and Hewett point out, sedentary jobs often have high hand dexterity and repetitive hand use demands (6). Early vocational rehabilitation is effective in reducing job loss (23), and such intervention may facilitate use of appropriate accommodations.

Although computer use has been increasing, little is known about the effect of RA on a person's ability to use a computer, and there is no information at all about how workers with RA are accommodating their computer work. It is known that computer use is a significant risk factor for musculoskeletal disorders of the upper extremity, such as carpal tunnel syndrome and tendonitis (24), and that individuals with rheumatic diseases are more at risk to develop such disorders than those without rheumatic diseases (25).

Occupational hand use was assessed in this study using one item that assessed extent of use. Although this is an important measure, specific types of hand use, such as power grip and dexterity, were not assessed. Specific types of hand use likely differ by occupation; although subjects with operator/facilitator/laborer jobs reported using their hands less extensively than those in other jobs, their hand actions may have required more grip strength and thus may have been more strenuous. Although our sample was national (US) and large, it did not include many members of minority groups, and its average educational attainment was higher than that of the US population. However, because we found extensive hand use in all types of jobs, we would anticipate that hand use would be equally extensive in a population-based sample.

This study demonstrated that occupational hand use was extensive in a large, US national sample of employed persons with RA. Study participants in all types of jobs experienced extensive hand use, and participants with extensive hand use were more likely to report having pain in the PIP or MCP joints. Although hand involvement is characteristic of RA and studies conducted to date suggest that many employed persons with RA have occupational hand use problems, very little research or clinical work has focused on this potentially serious problem. Studies are needed to document the extent and types of occupational hand use problems, especially for using computers, and the impact of such problems on employment. Clinical work is needed to develop and test accommodations.

Ancillary