Musculoskeletal Pain and Arthritis in MS and Other Subjects with Pain : Case Control Study

Background:

Subjects who sought treatment for acute or chronic musculoskeletal pain often have arthritis and related conditions. 300 subjects were reviewed: 36 (Cases) had multiple sclerosis; 228 controls (Cont.).

Objectives:

To measure relative frequency of arthritis in MS versus other patients with pain: case-control design matched for age and gender

Methods:

All data were retrospectively retrieved from medical records: vitals, problem list, medications, progress notes, imaging & lab data. Other covariates: pain location, type, and level; the Pain Disability Questionnaire (PDQ) & laboratory data; summed score of abnormal joints + spine (C/T/L). Main outcome measure was number of subjects with arthritis (from radiological report) in cases compared to controls. Secondary measures: pulse pressure; total, functional and psychosocial subscales of the PDQ, and pain type. Data analysis: IBM SPSS v.21, odds ratio (O.R.) from CEBM calculator. Stand. deviations and confidence intervals reported.

Results:

300 subjects during the 2 year time period. 55% of subjects were female. Mean age female = 56.2 (11.8); male = 58.1 (13.4).

Outcome:  O.R. was 0.69 [CI= 0.58-0.80].  This ratio implies that radiographic evidence of arthritis was less common in cases than controls. For the variable (spine + joints), score correlated with age, r = 0.336 [95% CI = 0.240-0.429], p < .001. Correlations analyzed by the number of joints involved across gender, chi square (X²) was 4.346, d. f. = 3, p = .226, not significant (NS).

For pain type, 24% had somatic pain, 29% neuropathic pain, and 43% mixed. Cross-tabulation (MS*controls) gave X² of 2.473, d. f. = 3, p= 0.482 [95% C.I. = 0.473-0.492], NS.

Pulse pressure differed between cases and controls. Mean (Cont.) was 51.3 (14.8) [95% CI = 49.4-53.3]; Cases = 44.3 (11.3) [95% CI = 40.8-48.1]. Mann Whitney U test was significant for group difference (p < .008). Regression (age = independent variable) showed a significant F test =19.072 (p <.001).  R value was 0.381, adjusted R² was 0.138. The regression equation: PP = 68.302-1.106X +0.103X² (X = age).

86% of subjects completed PDQ. Mean (Cont.) Functional subscale = 43.08 (19.7) [CI = 40.67-45.65]; Psychosocial = 25.28 (14.4) [CI = 23.46 – 27.21]; and Total PDQ 68.03 (31.9) [CI = 64.02 – 72.09]. Cases had means: Funct. 48.1 (17.5) [41.2-54.5]; Psych 27.1 (12.3) [22.03-32.36] and Total 75.1 (28.2) [64.5-87.1]. Between groups- ANOVA was NS.

Conclusions: Despite similar levels of pain, MS subjects had less frequent arthritis than controls with pain. Group differences in pain disability measures including psychosocial and functional did not show significance between groups. Pulse pressure was lower in MS subjects than controls, which differs from recent literature which has reported use of brachial PP as reliable measure of deconditioning. Our group of cases may be better conditioned than previously reports of deconditioning in MS.