Journal of Psychosomatic Research 52 (2002) 501–509 A rating scale for fibromyalgia and chronic fatigue syndrome (the FibroFatigue scale) Olof Zachrisson*, Bjo¨rn Regland, Marianne Jahreskog, Margareta Kron, Carl G. Gottfries Psychiatry Section, Institute of Clinical Neuroscience, Go¨teborg University, Go¨teborg, Sweden Received 6 February 2001; accepted 1 November 2001 Abstract Objective: To construct an observer’s rating scale sensitive to of both sexes. Results: The FibroFatigue scale is an observer’s change for measuring severity and treatment outcome in fibro- rating scale with 12 items measuring pain, muscular tension, myalgia (FM) and chronic fatigue syndrome (CFS) patients. fatigue, concentration difficulties, failing memory, irritability, Methods: A selection of items from the Comprehensive Psycho- sadness, sleep disturbances, and autonomic disturbances (items pathological Rating Scale (CPRS) were repeatedly rated and used as derived from the CPRS) and irritable bowel, headache, and outcome measure of a 24-week treatment study. In the study 100 subjective experience of infection (new items). There was a women, fulfilling the criteria for both FM and CFS, received statistically significant correlation between the CPRS-extracted intermittent injections of a staphylococcus toxoid or placebo. Nine items and global ratings as well as with the FIQ. The interrater CPRS-items with high baseline incidence (cutoff 70%) were reliability of the new scale was excellent (correlation coefficient extracted and validated against global ratings and the Fibromyalgia .98), irrespective of the patients’ gender. Conclusion: The Impact Questionnaire (FIQ). The fibromyalgia and chronic fatigue FibroFatigue scale seems to be a reliable and valid measuring syndrome rating scale (the FibroFatigue scale) was thereafter instrument with capacity to monitor symptom severity and change formed based upon the extracted items and three supplemented during treatment of FM/CFS patients. D 2002 Elsevier Science Inc. ones. The interrater reliability was tested in 27 consecutive patients All rights reserved. Keywords: Fatigue syndrome; Chronic; Fibromyalgia; Infection; Psychiatric status rating scales; Pain; Treatment outcome Introduction Treatment studies on FM/CFS have frequently used the Visual Analogue Scale (VAS) to obtain patient perception Fibromyalgia (FM) and chronic fatigue syndrome (CFS) data. The profile of mood has been estimated using rating are both chronic clinical conditions characterised by a scales for depression such as the Hamilton Depression variety of nonspecific symptoms, including prominent Rating Scale [5] and the Beck Depression Inventory [6]. fatigue, myalgia, and sleep disturbances. Despite different The Arthritis Impact Measurement Scales [7] and the diagnostic criteria, CFS and FM have many demographic Fibromyalgia Impact Questionnaire (FIQ) [8] are self-rating and clinical similarities with few differences in the domains instruments which have been used to assess functional of symptoms [1,2]. Both disorders seek their clinical recog- limitations and disability. They have been evaluated for nition and, so far, their diagnoses are based on criteria. reliability and validity in the FM population [9]. Self-rating There are no widely accepted pathogenic explanatory mod- scales are also provided for the evaluation of fatigue [10– els for either illness [2,3]. In spite of extensive research, 12] and one self-rating scale for screening CFS symptoms treatment continues to be of limited success [4]. has been published [13]. In a previous trial on FM/CFS [14], we found the neurasthenia subscale of the Comprehensive Psychopathological Rating Scale (CPRS) [15,16] useful for * Corresponding author. Psychiatry Section, Institute of Clinical Neuroscience, Sahlgrenska University Hospital/Mo¨lndal, SE 431 80 evaluation of treatment effects. Mo¨lndal, Sweden. Tel.: +46-31-343-2397; fax: +46-31-776-9055. Within psychiatry, observer’s rating scales are often E-mail address: [email protected] (O. Zachrisson). considered more valid and reliable than self-rating scales. 0022-3999/02/$ – see front matter D 2002 Elsevier Science Inc. All rights reserved. PII: S0022-3999(01)00315-4 502 O. Zachrisson et al. / Journal of Psychosomatic Research 52 (2002) 501–509 In this study, we wanted to construct a new observer’s rating Table 1 scale aimed at the assessment of core symptoms and treat- Incidence of symptoms (frequency of scores above zero) and mean score ( ± S.D.) on 15 items derived from the CPRS ment outcome in FM and CFS. Due to substantial overlap in symptomatology between FM and CFS, we decided to CPRS item Incidence (%) Score mean ± S.D. develop a scale suitable for both conditions. The scale 1 Aches and pain 100 4.8 0.8 should be based on the CPRS items that we had used within 2 Fatiguability 100 4.8 0.9 3 Reduced sleep 98 4.0 1.2 a double-blind treatment study and their psychometric prop- 4 Muscular tension 97 3.5 1.2 erties be tested against global rating scales [17] and the FIQ. 5 Concentration difficulties 95 2.8 1.3 6 Failing memory 93 2.7 1.2 7 Autonomic disturbances 93 2.5 1.2 Patients and ratings 8 Hostile feelings 83 2.2 1.4 9 Sadness 77 1.6 1.3 10 Inner tension 59 1.4 1.3 Patients 11 Worrying over trifles 55 1.3 1.4 12 Pessimistic thoughts 54 1.1 1.1 The present study was based on a group of 100 patients, 13 Suicidal thoughts 37 0.8 1.1 all women, aged 20–66 years [mean 47.8 years ( ± 11.1 15 Hypochondriasis 22 0.5 1.0 15 Phobias 18 0.4 1.0 S.D.)] who were evaluated in a 24-week double-blind clinical trial. In the trial, patients were given repeated Baseline ratings in 100 women fulfilling the criteria for FM and CFS. Each item is scored 0 (no symptom)to6(severe symptom). The nine first items subcutaneous injections of a staphylococcus toxoid vaccine were included in the final scale or placebo [18]. To be included in the research program, the patients had to fulfil the American College of Rheumato- logy (ACR) criteria for FM [19] and the 1994 criteria for where all the items have explicit definitions. Based on the CFS established by the CDC [20]. The patients were information obtained from a clinical interview, each item is referred to our unit from other units in the hospital but most scored 0 (absence of the symptom)to6(maximal degree of of them were referred by general practitioners. All patients the symptom). To aid scoring, a short description (anchoring included were chronically ill and many had been granted a point) is given for scores 0, 2, 4, and 6. If the patient’s sickness pension. On average, the patients had been suffer- condition falls somewhere in between the anchoring points, ing from FM symptoms and chronic fatigue for 11.5 years a score of 1, 3, or 5 (which are not defined) may be given. (range 1–40 years). Due to ethical considerations, the These undefined points increase the scale’s sensitivity to patients were allowed to keep to their prescribed drug change [22]. The reliability has been shown high between regimens during the study. The most common medication disciplines (psychiatry, general practice, nursing, and psy- was analgesics, which were used by 79% of the patients. chology) and the instrument has been shown highly sens- Antidepressants (low doses of tricyclics or selective sero- itive during trials on various psychiatric groups of patients tonin reuptake inhibitors) were used by 42%, hypnotics by (e.g., depression, schizophrenia) [23]. The Montgomery– 26%, daytime benzodiazepine by 21%, and medications for Asberg rating scale for depression [24] and the GBS rating gastrointestinal problems by 19%. Seven patients (7%) did scale for dementia syndromes [25] are examples of estab- not use any concomitant medication. lished rating instruments derived from CPRS. CPRS has been shown useful also in nonpsychiatric patients, e.g., Scales used to design and validate the FibroFatigue scale obstructive sleep apnoea [26], stroke [27], and workers exposed to organic solvents [16]. The fibromyalgia and chronic fatigue rating scale (the Clinical Global Impression, severity of illness (CGI-S) FibroFatigue scale) was derived from 15 items of the [17] is a 7-point global assessment scale with items ranging neurasthenia subscale of CPRS [15] (Table 1). The ratings from normal to among the most severely ill, where the were performed within the study by three registered nurses observer, after an examination or interview, assesses the trained by an experienced CPRS rater. An interview was patient’s severity of illness. In the present study, CGI-S done at baseline, and new interviews were done once a assessments were made prior to the study and at the end of month during the 24-week trial. At every interview, the same the study by the same rater. rater, who was blinded to whether the patient was given Clinical Global Impression of change (CGI-C) [17] is a active treatment or placebo, assessed the patient. The dura- 7-point global assessment scale with items ranging from very tion of the interview varied but was usually less than 20 min. much worse to very much improved, where the observer The original CPRS [21] comprises 65 items covering a makes an assessment of change in degree of illness in relation broad range of psychiatric symptoms both of neurotic and to the previous assessment. In the present study, each psychotic dimensions. The scale was intended for treatment patient’s condition at the end of the study was compared with evaluation and to serve as a pool from which items could be her condition at admission by the same rater using the CGI-C. selected to construct scales for various syndromes. The The Fibromyalgia Impact Questionnaire (FIQ) [8] is a CPRS is a semistructured interview-based rating instrument 10-item self-report instrument developed to measure the O.