Objectives: To study prospectively the health status, and especially the physical functioning, of polio survivors with and without postpoliomyelitis syndrome (PPS), and to identify prognostic determinants of change in physical functioning.
Design: Prospective cohort study; measurements at baseline and after 1, 2, and 6 years.
Setting: University hospital in the Netherlands.
Participants: Seventy-six subjects with PPS and 27 without PPS.
Interventions: Not applicable.
Main outcome measure: The Nottingham Health Profile (NHP) physical mobility category.
Results: Subjects with PPS had significantly poorer health status than subjects without PPS. No significant differences in mean NHP physical mobility scores between baseline and 6 years were found; both groups had improved after 1 year, after which there was a slow decline over the next 5 years. During the first 2 years, strength measurements showed little decline that was not related to changes in NHP physical mobility score. A physical performance test revealed no mean change in the first 2 years, but the subgroup with a decline above the 75th percentile eventually deteriorated 10.5+/-16.3 points on the NHP physical mobility category (P=.01) at 6 years from baseline. This subgroup had more extensive paresis than the other subjects, although it was not significant (P=.07). The extent of paresis at baseline was the only prognostic determinant for an increase in NHP physical mobility problems after 6 years.
Conclusions: Subjects with and without PPS did not differ with regard to changes in health status in a 6-year period. The fact that the extent of paresis was a prognostic factor for a decline in physical functioning is in accord with a (slow) decline in muscle mass, as a late effect of polio, that may lead to a decline in physical functioning as the reduced muscle capacity becomes less able to meet the demands of daily physical activities.