Functional and environmental factors affecting work status in individuals with longstanding poliomyelitis

Abstract

Introduction

Remunerative employment is a major concern of individuals with chronic disabilities, among them, those with longstanding poliomyelitis (LSP). Although LSP is not rare there are almost no data related to work participation.

Purpose

The aims of the current study were to determine the effects of a number of social and functional variables as barriers or facilitators to work participation in persons with LSP.

Patients and methods

Charts of 123 LSP patients of working age that were seen in the post-polio outpatient clinic, between the years 2000 and 2005 were reviewed for the study. Data on age, gender, family status, level of function in activities of daily living, basic, and extended (B-ADL and E-ADL), and mobility were then analyzed for correlation to the vocational status.

Results

Seventy-two people (58.5%) were employed at the time of the survey. Gender and marital status were not found to significantly differ as regard to employment. Using assistive devices for mobility or being dependent for basic ADL were associated with lower levels of employment. Driving was positively associated with the employment status of the LSP individuals.

Conclusion

Persons with LSP encounter important barriers to work participation, particularly on the International Classification of Functioning, Disability, and Health (ICF) components of activity and environment.

Introduction

While people with poliomyelitis usually remain relatively stable with regard to the primary neurological impairment, many develop deterioration due to the effects of aging with altered neurophysiology and biomechanics. In addition, there are those who go on to develop the post-polio syndrome (PPS). PPS is characterized by the onset of new muscle weakness not due to other pathology and is often associated with pain and fatigue, after 15 or more years of stability^1,2 There is a wide range in literature of those thought to have PPS. The World Health Organization (WHO) estimates that there are up to 20 million polio survivors in the world; more than 1 million in the USA; and that 80% experience symptoms consistent with PPS after age 40.³

In a ‘special communication’, Halstead cited significantly fewer polio survivors, and a much smaller proportion having symptoms of PPS.⁴ The wide range was explained by Laban⁵ who noted that in his vast experience, there are many identifiable causes of deterioration in this group, and that true PPS is quite rare. The epidemiological studies reporting large numbers do not define the steps that were taken to assure that other etiologies were excluded.⁵ We designated individuals with polio and deterioration, including those with PPS, as having longstanding poliomyelitis (LSP). In Israel, most post-polio survivors were affected by the acute disease in the 1950s, and over time, many developed LSP. Individuals with chronic disabilities experience a higher unemployment rate than those without disabilities.^6–8

Employment rates vary greatly according to severity of impairment of body function, level of activity, environmental conditions, and individual factors. Increase in weakness, pain, fatigue, or other secondary changes such as in bowel and bladder control, cognitive deterioration, depression, as well as deterioration of ambulation may influence work performance and ability to remain in the work force. Social variables and environment issues may also serve as barriers or facilitators to employment for people with disabilities.⁹ In Israel, there is still a lack of accessibility in many public buildings and public transportation, while the National Insurance Institute (NII) assists with funding for adaptive equipment, cars, and attendant care.

The NII for social security established a system for assignment of levels of disability as per specific listed criteria. A disability pension is paid to a person whose earning capacity is reduced by 50% due to disability, or to a housewife whose ability to function in her household is reduced by 50%. Each applicant for disability undergoes a specialist medical evaluation, with the potential for multiple evaluations, depending on the type, and combination of health conditions and impairments. In 2003, approximately 200 000 people with disabilities aged 18–65 years received various types of benefits from the NII (∼5% of the adult population). This number does not include people with disabilities who are employed and whose salary exceeds the maximal sum allowed for the disability benefit. Nearly 20%, of recipients of the disability benefit have motor impairments, while people with mental illnesses and disturbances represent 30% and internal medicine disorders (e.g. cancer, heart, and kidney) represent 25%. Among recipients of the general disability benefit from the NII, only 15% are employed.¹⁰

The Ministry of Health provides mobility aids (including orthoses, prostheses, and wheelchairs) according to criteria of level of impairment and activity. Employment has been widely studied among persons with neurological disabilities, especially in those with spinal cord injury.^6,11,12 Lidal et al.¹³ found that only 20–40% were employed 10 years or more after the injury. Most of those who did return to work required assistive technology, support services, and counseling.¹⁴

Thirty percent of individuals with multiple sclerosis remain employed 5 years post-diagnosis. They similarly need assistance and modifications as is the case with individuals with spinal cord injury.¹⁵

The effect of LSP on employment rate has also been reported.^8,16 Weakness, fatigue, and pain are the most common medical obstacles to employment in those with LSP. Forty percent report that fatigue interferes with their ability to continue to work. A recent report from Israel showed that 47% of polio survivors were employed.¹⁷ However, there are no available data regarding functional, environmental, and personal factors that impact on work participation among these individuals.

The hypothesis of this study is that in LSP, those who work have fewer barriers and more facilitators than those not working. An additional hypothesis is that lower grade walking aids are associated with higher employment rates.

Patients and methods

Out of 158 individuals with LSP, 123 were of working age (<65 years for men and 60 years for women). All were treated in the ‘post-polio’ outpatient clinic during the years 2000–2005. Most had onset of acute poliomyelitis approximately 50 years ago during the epidemics of the fifth and sixth decades of the twentieth century.

Two of the authors (YS and ID) reviewed the medical records and extracted the data.

Employment was defined as at least 20 hours per week of regular remunerative activity. The following data were collected: age, gender, family and parental status (Table 1), activities of daily living, basic and extended (B-ADL and E-ADL), and mobility status. (Table 2) The B-ADL status was expressed as either being independent or needing of any level of assistance in self-care (washing oneself, toileting, dressing, eating/drinking). The E-ADL status was expressed as either being independent or needing any level of assistance in domestic life (preparing meals and housekeeping). The mobility level was defined according to the need for and type of assistive device: (1) none or adapted shoes; (2) use of orthosis(es); (3) walking aids such as crutches or walker (with or without orthosis) or wheelchair. Mobility was further classified according to indoor and outdoor ability. Driving status was also determined. Barriers and facilitators of working participation were defined according to the International Classification of Functioning, Disability and Health (ICF) model.¹⁸

Table 1.

Demographic data

		Employed	Unemployed	P-value
		(N = 72)	(N = 51)
Gender	Male	29 (40%)	23 (45%)
	Female	43 (60%)	28 (55%)	0.59
Age (years)		53.9 (SD = 6.2, N = 72)	53.3 (SD = 6.9, N = 51)	0.7
Time from disease diagnosis (years)		52.4 (SD = 6.0, N = 68)	51.2 (SD = 8.6, N = 47)	0.69
Birth country	Israel	51 (72%)	36 (72%)
	Other	20 (28%)	14 (28%)	0.98
Marital status	Married	57 (79%)	38 (78%)
	Divorced	2 (3%)	6 (12%)
	Widow	4 (5%)	0 (0%)
	Single	9 (13%)	5 (10%)	0.078
Number of children		2.4 (SD = 1.5, N = 72)	2.3 (SD = 1.5, N = 49)	0.90

Table 2.

Functional independence and ambulation

		Employed	Unemployed	P-value
		(N = 72)	(N = 51)
Driving	Yes	62 (86%)	36 (72%)
	No	10 (14%)	14 (28%)	0.054
Use Wheelchair∧	Yes	14 (20%)	10 (22%)
	No	57 (80%)	35 (78%)	0.74
Independence in basic activities of daily living (B-ADL)∧	No	13 (19%)	16 (36%)
	Yes	57 (81%)	28 (64%)	0.034
Independence in expanded activities of daily living (E-ADL)∧	No	45 (76%)	37 (86%)
	Yes	14 (24%)	6 (14%)	0.21
In-house mobility aids∧	None/adapted shoes	41 (57%)	22 (45%)
	Orthotics	2 (3%)	8 (16%)
	Walking aids or wheelchair	28 (40%)	19 (39%)	0.011*
Out-of-house mobility aids∧	None/adapted shoes	33 (46%)	15 (31%)
	Orthotics	7 (10%)	10 (21%)
	Walking aids or wheelchair	31 (44%)	23 (48%)	0.041*

*Using the test by Robertson and Wright (1981).

^∧Complete data were not available for all the patients.

Statistical methods

Statistical analysis was performed by a trained biostatistician (A.H.) using R 2.7.2 (R Development Core Team, Vienna, Austria)¹⁹ Categorical variables are presented as frequency (% percent). The distributions of categorical variables between employed and unemployed patients were compared using the chi-square test of independence.

The distributions of ambulation aids between employed and unemployed post-polio patients were compared using the likelihood ratio test for ordered multinomial data by Robertson and Wright.²⁰ This test takes into consideration the ordered nature of the categories, i.e., none is better than an orthosis which in turn is better than supporting aids. P-value estimation was done using the chi-bar distribution.

Continuous variables were checked for normal distribution by the one-sample Kolmogorov–Smirnov goodness-of-fit test. If normal distribution was found, the comparison between employed and unemployed patients was done by independent sample t-test. When normal distribution was rejected the Wilcoxon–Mann–Whitney rank sum test was used for comparison between the aforementioned two groups.

Complete data were not available for all the patients. Missing data were excluded from analysis, with the number of patients for whom data were available is written (for continuous variables). P-value less than 0.05 was considered to be statistically significant. Except for P-values used in the Robertson–Wright test,²⁰ all other P-values used were two-sided.

Power analysis shows that the current study has a 70% power to detect a difference in none ambulation aids of 46% and 31% in the employed (72 patients) and unemployed (51 patients) groups, respectively. Post hoc power analysis was performed.

Multivariate logistic regression was performed using categorical dichotomous (0 = employed and 1 = unemployed) as the response variable. Explanatory variables included driving, independent B-ADL, independent E-ADL, walking aids used out and indoors. Stepwise model selection was performed to determine the most important covariates in the model.

Results

Our study included 123 working-age persons with LSP (52 men, 71 women). Seventy-two (58%) were employed and 51 (42%) unemployed. Table 1 presents demographic data split to employment groups. None of the demographic variables showed a statistically significant difference between the employed and unemployed (Table 1).

Table 2 presents the data for functional and mobility status. Of the overall group 80% (98) drove a car adapted to their disability. The driving/non-driving ratio in the employed group was higher than in unemployed group. This difference approached but did not reach statistical significance (P = 0.054).

B-ADL status was found to be statistically significant with 81% of the employed being fully independent as compared to 64% of the unemployed (P = 0.034). On the other hand, the level of independence in E-ADL did not reach a level of statistical significance.

Use of assistive devices for mobility both in-house and out-doors was found to differ among employed and unemployed patients. The difference between groups was found to be statistically significant both in-house (P = 0.011) and out-doors (P = 0.041).

However, the use of orthoses was the only influencing factor, while there was no difference between the two groups for walking aids and wheelchair use as an independent variable.

Multivariate logistic regression recognized independence in B-ADL as the only statistically significant covariate influencing employment status (P-value = 0.032). The odds ratio for employment of a B-ADL-independent person was 2.8 (95% confidence interval 1.09–7.19) as compared to a B-ADL-dependent person.

Discussion

Work participation represents a key step towards full positive community integration of people with disabilities and is correlated with a higher quality of life.^21,22

Although acute poliomyelitis is now very rare in industrialized countries,²³ many survivors of the major polio epidemics that occurred during the 1940–1950s have gone on to develop LSP. There are still many new cases of acute poliomyelitis in developing countries.¹ PPS is defined by new or increased neurological deficits that cause an aggravation of the impairments and disabilities, and destabilizes the existing functional and social equilibriums that were achieved over the years. Even among those who do not meet the criteria of PPS, most are still characterized as having LSP as they experience deterioration in their status due to the effects of aging with the disability.

Almost 60% of the persons with LSP in our study were employed at the time of the study. This relatively high employment rate in persons with LSP is similar to a previous report from Israel,¹⁷ and from other countries.^1,8,24,25

Populations with other severe neurological disabilities, such as spinal cord injury, have been found to have significantly lower employment rates than our group with LSP.^11,26 A possible explanation is the young age at the time of the acute episode of poliomyelitis followed by successful physical, mental, and environmental adaptations. The awareness of the level of impairment and disability leads to decisions that optimize resources in the areas of education, profession, and social milieu. The employment rate in pediatric-acquired SCI was found to approach that of LSP, presumably for the same reason.²⁷

We also assume that there is a relatively lower level of impairment of our LSP group when compared with other severe neurologically disabled populations such as spinal cord injury, stroke, and traumatic brain injury. Specifically, cognition and sphincter continence are not affected by polio, and thus these factors do not adversely influence work participation in our study group. Social variables, such as marital status or having children, which may have been thought to impact on the likelihood of employment, were not found to have been statistically significant in our study (Table 1). These findings may again be indicative of the high level of adaptation to the disease and disability achieved by this population.

In our study, dependency in B-ADL was the only statistically significant factor limiting work participation. Driving was suggestive of facilitating the occupational status among this population. Our hypothesis that greater mobility aids (walking aids or wheelchair) would present a barrier to employment was not demonstrated, even though use of orthoses was suggestive of being a limiting factor to work participation. While dependency in basic activities and restrictions in mobility were found to represent major limitations to work participation among other health conditions such as traumatic brain injury,²⁸ stroke,²⁹ amputations,³⁰ and spinal cord injury,^11,12 driving a car as a facilitating factor of employment was seldom described.³¹

There are many potential explanations for B-ADL dependency being a barrier to work participation. The relative increased time to perform the ADL tasks without assistance, or the lack of availability of a caregiver to facilitate the ADL tasks due to financial constraints would clearly make active employment more difficult. In addition, a previously independent individual who now needs assistance for basic living may become depressed, adversely impacting the drive to remain employed. Raising the awareness of the need for capable caregivers, supportive technologies, and increasing the financial support may lower these barriers as well.

Among individuals with limitations in mobility, individuals using an orthosis were less likely to be working. It is clear that the use and type of orthosis is indicative of the level of impairment of the body functions and structures. Nevertheless, an individual with a specific level of body impairment may be fitted with a range of differing orthoses. The role of orthoses in these individuals is primarily for supporting and controlling joints, and reducing the impact of bodyweight, particularly on the legs and feet. The use of orthoses should improve parameters of ambulation, such as, stability, speed, and energy expenditure, as well as reduce pain and overuse injuries of the muscles, joints, tendons, and ligaments. In reality, orthoses may fall short of these target benefits. For example, energy consumption may be high when walking with a standard KAFO (Knee Ankle Foot Orthosis), while use of a lightweight KAFO may decrease oxygen consumption during walking and save energy.^32,33 Individuals with LSP, especially those with PPS, should be supplied with appropriate orthoses on the basis of individual needs.^34,35 To further improve energy efficiency, carbon-composite material is often preferred.^29,30,36 Previous studies have indicated that walking with a carbon KAFO, does reduce the oxygen consumption; oxygen cost and physiological cost index, when compared with an ordinary KAFO in patients with PPS.³³

Crutches, manual and electrical wheelchairs, and scooters have the potential to further increase functional activity when meaningfully used.³² Interestingly, the use of a wheelchair in our study was not a significant factor in employment. However, there are manual wheelchair users who have secondary pain or limited endurance. For these individuals, pushrim-activated power assisted wheelchairs have become a viable option to improve function and reduce injuries from overuse.³⁷ Broader accessibility to new technologies in the design and function of orthoses and wheelchairs may improve work participation and quality of life.

Driving was suggestive for positively influencing employment. The new assistive technologies in the field of adapted cars for people with disabilities allow almost every physically disabled individual, regardless of the specific health condition, and level of disability to drive a car. The remaining obstacles to be resolved are the lack of awareness of potential technical solutions and the means for financing the necessary modifications.

A pitfall in this type of study is that the findings are based on a single point in time. As such, it does not provide a dynamic picture of the employment status over the course of time in those with LSP. A study that tracks employment changes over time, including the specific reasons for the termination of employment in each case would provide significant further information as to barriers and facilitators of employment in this population. Another issue is the combining of those with true PPS along with those suffering deterioration due to sequela of acute polio. There may be specific barriers and facilitators related to each of the groups.

Conclusion

The majority of LSP individuals in our study were employed at the time of the study. There are factors that were determined to be barriers and facilitators to employment. The identification of these factors may enhance our ability to further increase gainful employment. In order to achieve these goals, there is a need for integrating the efforts of the individual with LSP, the medical providers and the support from the appropriate governmental and insurance agencies. Further epidemiological studies studying barriers and facilitators of employment would likely provide additional details to refine the treatment and resources needed to maximize the work status of these individuals.