Development and factor analysis of an index of post-polio sequelae

The value of a post-polio syndrome self-management programme

Background

Post-polio syndrome is characterised by symptoms of fatigue, pain and new-onset neuromuscular weakness, and emerges decades after the initial poliovirus infection. We sought to evaluate the only post-polio syndrome specific self-management programme in the United Kingdom.

Methods

This was a retrospective study of patients who had completed a residential self-management programme led by a multi-disciplinary clinical team. Following a confirmed diagnosis of post-polio syndrome by rehabilitation and neurology specialists, patients were offered to participate in the programme. Although group-based, patients also received individually tailored support on physical exercise and fatigue management. Physical effects, physical function, psychosocial well-being measures were assessed at baseline and 6 months follow-up. Knowledge was tested at baseline and immediately following the programme. Statistical comparisons were made using paired t-test and Wilcoxon signed rank test according to the data distribution.

Results

Over a period of 17 years, 214 participants (median age 61.3 years old, 63% female) attended 31 programmes. At 6 months the following post-polio syndrome specific symptoms improved significantly: fatigue, as measured by the Multidimensional Assessment of Fatigue scale [37.6 (7.1) vs. 34.2 (9.3), P=0.005]; and pain [15.0 (6.1) vs. 13.1 (6.7), P=0.001], atrophy [10.0 (8.0–12.0) vs. 9.0 (7.0–11.0), P=0.002] and bulbar symptoms [3.0 (1.0–5.0) vs. 2.0 (0–4.0), P=0.003] as measured by the Index of Post-polio Sequelae scale. Knowledge related to post-polio syndrome also significantly increased [14.0 (11.0–16.0) vs. 17.0 (16.0–19.0), P=0.001]. Participants were able to walk at a faster speed over 10 meters [0.77 (0.59–1.00) vs. 0.83 (0.67–1.10) m/s, P=0.003] and walked longer distances during the 2-minute walk test [76.9 (31.7) vs. 82.0 (38.4) m, P=0.029]. Depression and anxiety scores did not change over time [PHQ-9, 2.0 (0.3–10.8) vs. 2.0 (0.3–6.8), P=0.450; GAD-7, 2.0 (0–7.0) vs. 1.0 (0–3.0), P=0.460] nor was there change in self-reported quality of life {60 [50–70] vs. 60 [55–70], P=0.200}.

Conclusions

This study suggests that a post-polio syndrome self-management programme led to improvement in symptoms, knowledge and walking speed, but not quality of life. Anxiety and depression scores remained low.

Health-related quality of life, self-reported impairments and activities of daily living in relation to muscle function in post-polio syndrome

BACKGROUND

The symptoms of post-polio syndrome (PPS) and its resulting disabilities can affect quality of life and the ability to perform daily activities. No study has comprehensively analysed how various patient-reported outcome measures (PROMs) are associated with objectively assessed physical function in patients with PPS.

AIM

To investigate health-related quality of life (HRQOL), self-reported impairments and activities of daily living during 6 months and evaluate their association with clinical muscle function outcomes in individuals with PPS.

METHODS

Twenty-seven patients with PPS were included in the study. At baseline and 6 months, patients were administered PROMs measuring HRQOL (WHOQOL-BREF), self-reported impairments related to PPS (SIPP-RS) and activities of daily living (IBM-FRS). Clinical muscle function outcomes included 6 min walking distance (6MWD) and motor function measure (MFM).

RESULTS

There were no changes in self-reported impairments (25.52 to 24.93, p = 0.40), activities of daily living (33.89 to 33.30, p = 0.20), 6MWD (391.52 to 401.85, p = 0.30) and MFM (83.87 to 85.46, p = 0.14) during 6 months, while the HRQOL psychological health decreased during this period (76.85 to 72.38, p = 0.05). A strong association was found between activities of daily living and clinical muscle function outcomes (6MWD: ß = 0.02, 95% CI: 0.02;0.03, t = 6.88, p < 0.01; MFM: ß = 0.25, 95% CI: 0.17;0.33, t = 6.69, p < 0.01). Self-reported impairments and HRQOL domains were not associated with the clinical muscle outcomes.

CONCLUSIONS

Study findings indicate that objectively measured walking and motor abilities do not reflect patient's perspectives of their HRQOL and impairment due to PPS. More research is needed to assess changes over time and capture clinically meaningful changes in individuals with PPS and to increase the understanding of how the patient's perspective of disability measured by PROMs is related to objectively measured walking and motor abilities.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier ( NCT02801071 ) registered June 15, 2016.

Construct validity of a new rating scale for self-reported impairments in persons with late effects of polio

OBJECTIVE

To evaluate the construct validity of a new rating scale for self-reported impairments in persons with late effects of polio.

DESIGN

Psychometric analysis of data on self-perceived impairments in persons with prior polio.

PARTICIPANTS

Two hundred seventy-three persons with prior polio (119 men and 154 women; mean age, 63.5 years).

METHOD

Rasch analysis of a 13-item rating scale with 5 response categories, in which the participants rated how much they have been bothered by various post-polio-related impairments during the past 2 weeks.

RESULTS

The initial analysis showed disordered categories, misfit with some of the items, multidimensionality, and local dependency. After adjustment of the categories, which resulted in a 4-category rating scale, fit to the model was achieved, but the scale still showed signs of multidimensionality. Analyses of local dependency revealed correlations among some of the items, which resulted in a 5 testlet solution, which gave fit to the model and unidimensionality.

CONCLUSION

After adjustment of the categories and local dependency, this new rating scale, Self-Reported Impairments in Persons With Late Effects of Polio, can be considered as unidimensional. The good psychometric properties implies that the Self-Reported Impairments in Persons With Late Effects of Polio scale could be a useful rating scale that would increase our understanding of the impairments that persons with late effects of polio can experience. With further refinements, this scale may assist in the planning and evaluation of appropriate rehabilitation interventions.

Psychometric properties of the Fatigue Severity Scale in polio survivors

The objective of this study was to evaluate by means of classical test theory and Rasch analysis the scaling characteristics and psychometric properties of the Fatigue Severity Scale (FSS) in polio survivors. A questionnaire,consisting of five general questions (sex, age, age at time of acute polio, sequelae of polio, and new symptoms), the FSS, and three questions from the Visual Analog Scale questions on fatigue was sent to all 196 polio survivors at the Institute for Rehabilitation in Ljubljana. Responses were assessed in terms of Cronbach's a, item-to-total correlation, factor analysis, and Rasch analysis. Of the128 (65.3%) valid questionnaires returned, those presenting no missing values were used for subsequent analyses (n = 117). The FSS showed good internal consistency: Cronbach's a was greater than 0.95,item-to-total correlation ranged from 0.68 to 0.88. A reduction from seven to three rating categories was necessary to comply with criteria for correct category function. Item difficulty estimates spanned from – 0.91to + 1.09 logits. No item bias was found for sex and age.The internal consistency of FSS was high and its item separation reliability good, indicating a satisfactory replicability of item placement in other samples. In conclusion, Rasch analysis enabled us to confirm the validity of FSS (in its 8-item version, without item 1) as a measure of the severity and impact of physical symptoms of fatigue in polio survivors, so providing a useful starting point for further studies aimed at examining additional psychometric aspects and confirming the appropriateness of the simplification of its rating categories.

Quality of life and menopause in women with physical disabilities

OBJECTIVE

The goal of this cross-sectional study was to explore quality of life (QOL) in a sample of postmenopausal women with physical disabilities due to polio contracted in childhood. A structural equation model was used to confirm that menopause symptoms will have a minimal effect on QOL when disability-related variables are taken into account.

METHODS

A sample of 752 women who were postmenopausal completed a written survey. The structural equation model contained two measured predictors (age, severity of postpolio sequelae) and one latent predictor (menopause symptoms defined by four measured indicators). Functional status (defined by two measured indicators) was included as a mediator, with QOL (defined by three measured indicators) as the outcome.

RESULTS

The original model yielded acceptable fit indices (CFI = 0.96, RMSEA = 0.055) but resulted in a number of unexpected relationships that proved to be artifacts after model respecification. The respecified model yielded a nonsignificant chi-square value, which indicated no significant discrepancy between the proposed model and the observed data (chisquare = 18.5, df = 13, p = 0.138). All fit indices indicated a good fit: CFI = 0.997, NNFI = 0.987, chi-square/df = 1.43, and RMSEA = 0.024.

CONCLUSIONS

When the effects of postpolio sequelae and functional status are included in the structural equation model, only the psychological symptoms of menopause play a prominent role in explaining QOL in this sample. The clinical implications of these findings suggest that attention to psychological symptoms and an exclusive focus on the physical aspects of menopause to the exclusion of other midlife life stressors and influences on a woman's psychological well-being ignore the larger context of life in which they live. In particular, many women with disabilities may contend with additional or exacerbated stressors related to their disability.