Fibromyalgia (FMS), a condition traditionally defined by the presence of chronic widespread pain and tenderness, represents the tip of the iceberg of chronic pain in the general population. Estimating the prevalence of FMS is challenging, as many cases go undiagnosed.
We have attempted to estimate the prevalence of FMS in the Israeli population, using the London Fibromyalgia Epidemiology Study Screening Questionnaire (LFESSQ), an instrument previously utilized in several European countries.
The London Fibromyalgia Epidemiology Study Screening Questionnaire (LFESSQ) is an epidemiological tool recently implemented in a number of European countries for evaluating the prevalence of FMS. The questionnaire includes two components, the LFESSQ-4, screening for widespread pain, and the LFESSQ-6, which screens for both widespread pain and chronic fatigue. The pain criteria include 4 questions regarding musculo – skeletal pain in the upper or lower limbs or in the spine. The LFESSQ-6 adds two fatigue criteria (fatigue and limitation of activity due to fatigue).
The LFESSQ was administered via telephone to a representative sample of 1019 individuals selected by the quota method. A positive screen was defined as: (1) meeting the 4-pain criteria alone (LFESSQ-4), or (2) meeting both the 4-pain and 2-fatigue criteria (LFESSQ-6). To estimate the positive predictive value (PPV) of LFESSQ-4 and LFESSQ-6, this questionnaire was submitted to a sample of consecutive rheumatology outpatients (n=64, 17 males), who were then examined to confirm the diagnosis of FMS according to the 1990 ACR criteria. The prevalence of FMS in the general population was estimated by applying the PPV to eligible community subjects (i.e. positive screens).
In the community survey 5.1% and 3.92% screened positive for LFESSQ-4 and LFESSQ-6, respectively. Among males interviewed, 3.0% and 2.2% screened positive for the LFESSQ-4 and LFESSQ-6, respectively, while among females 7.1% and 5.6% screened positive for the LFESSQ-4 and LFESSQ-6, respectively.
Among rheumatology outpatients, 41.5% screened positive for LFESSQ-4 and 33.8% for LFESSQ-6, whereas 21.5% were confirmed FMS cases. Based on positive
screens for LFESSQ-4, the prevalence of FMS was estimated at 2.64% in the Israeli general population. The corresponding figure was 2.49 % if positive screens for LFESSQ-6 were considered. Among males, the prevalence of FMS based on the LFESSQ-4 was 1.55%; based on the LFESSQ-6 the prevalence was 1.4%.
Among females the prevalence based on the LFESSQ-4 was 3.68% and based on the LFESSQ-6 it was 3.56%.
The prevalence of FMS in the Israeli population is considerable, as estimated by the use of the LFESSQ, and constitutes a significant health care issue. The prevalence is similar to that observed in other western populations.
Using the LFESSQ-4 and the LFESSQ-6 yields similar results, but the LEFSSQ-6 appears more accurate, having a higher PPV for an individual meeting ACR criteria for FMS. The LEFSSQ-6 also addresses fatigue, recognized as a central clinical feature of FMS. Based on this tool, over 25% of FMS cases appear to be males, a proportion higher than generally appreciated.
Disclosure: J. N. Ablin, Pfizer Inc, 2 ; A. Oren, None; S. Cohen, None; V. Aloush, None; O. Elkayam, None; Y. Wolman, None; M. Berman, None.