Prevalence and Antecedents of Fibromyalgia in elderly women

Background/Purpose: Although epidemiological studies demonstrate that fibromyalgia (FM) prevalence increases with age, there have been no large-scale studies of FM in the elderly. In the clinic, elderly subjects usually receive treatment for common problems like diabetes, hypertension, back pain syndromes and other chronic illnesses; and the presence of FM is rarely recognized. In 2013 we performed a pilot study to estimate FM prevalence in the elderly by studying 882 women participants of the Women’s Health Initiative (WHI). Because the WHI study is longitudinal, we used prior data to investigate factors that predicted subsequent FM development.

Methods: In 2013, we administered the 2010 modified American College of Rheumatology (ACR) survey criteria questionnaire to 882 randomly selected WHI participants. We utilized a wide range of questionnaire data that had been collected at WHI enrollment 16 years previously, including a range of questions from the SF-36, CESD depression scale, symptoms scales, and other questionnaires. We used logistic regression and baseline variables to predict current FM.

Results: In 2013, the age of participants was 78.4 (SD 6.0) and they had been followed by the WHI for 16.4 years. The (2013) prevalence of fibromyalgia was 6.6% (95% CI 4.9-8.2). The average questionnaire scores in the population were: widespread pain index (WPI, 2.8 (2.8)), the symptom severity scale (SS, 2.9 (2.3), and the polysymptomatic distress score (PSD – sum of WPI and SS) 5.7 (4.3). To identify predictors of FM at initiation, we first excluded possible FM cases (15%) at study onset from further analysis if they reported moderate or severe body pain during the past 4 weeks. Of the remaining 746 subjects, the 2013 FM prevalence was 4.7% (3.1-6.2). In univariate analyses the following variables predicted FM 16 years later: social function, physical function, body pain, pain interference, general health, energy/fatigue, sadness in last two weeks, upset stomach, depression, headaches, low back pain, neck pain, diarrhea, aches and pain, constipation, and tiredness. In multivariate analyses, the following variables were included after backward stepwise regression filtering: constipation, pain severity, general health, energy/fatigue, neck pain, pain interference, and aches and pains. The area under the ROC for the final logistic model was 0.85.

Conclusion: Fibromyalgia (by criteria) was common in WHI participants as they approached 80 years of age. FM appeared to develop primarily in those baseline pain, aching, fatigue, impaired general health, and GI symptoms. Psychological factors did not seem to be important predictors.