FiRST Screening Positivity Among Patients Attending a Tertiary Chronic Pain service in Oman

Abstract

Objective

To estimate the Fibromyalgia Rapid Screening Tool (FiRST) screening positivity and its sociodemographic associations among adults attending a tertiary chronic pain service in Oman.

Methods

This cross-sectional study recruited 401 adults with chronic pain at the Royal Hospital in Muscat between January 2023 and January 2025. Participants completed the six-item Arabic-Egyptian FiRST; scores ≥5/6 defined as positive screening. Descriptive statistics were used to summarize participant characteristics. Bivariate analyses used Pearson’s chi-square test, with crude odds ratios (ORs) and 95% confidence intervals (CIs) for categorical predictors. Variables with P < 0.20 in bivariate analyses and clinically relevant variables selected a priori were included in the multivariable logistic regression. Adjusted ORs with 95% CIs were reported for the results.

Results

Overall, 170/401 participants screened positive (42.4%; exact 95% confidence interval [CI] 37.5–47.4%). Female sex was associated with higher adjusted odds (OR 1.723, 95% CI 1.065–2.787; P=0.027), while participants aged 40–59 years had lower adjusted odds than those aged 18–39 years (OR 0.528, 95% CI 0.317–0.879; P=0.014). The estimate for participants aged ≥60 years was imprecise and not statistically significant (OR 0.535, 95% CI 0.273–1.049; P=0.069). Family relationships, marital status, and academic level were not significantly associated with screening positivity after adjustment.

Conclusion

FiRST screening positivity was common in this tertiary pain population in Oman. Female sex and age 40–59 years compared with 18–39 years were associated with screening positive. A positive FiRST screen requires further clinical assessment and does not establish fibromyalgia, central sensitization, or central pain syndrome.

Introduction

Fibromyalgia (FM) is a complex chronic pain condition characterized by widespread pain and a range of associated symptoms, including fatigue, sleep disturbances, cognitive difficulties, and functional impairment. Fibromyalgia is considered an archetypal nociplastic pain disorder. The current understanding emphasizes the interacting biological, psychological, and social mechanisms rather than a single pathophysiological process.^1–3

Fibromyalgia can substantially affect physical functioning, quality of life, work participation, and healthcare utilization and is associated with a considerable economic burden.^4,5 These consequences make timely recognition clinically relevant, particularly in patients presenting with persistent or widespread chronic pain.

Historically, female sex and middle age have been described as characteristics associated with FM, although estimates vary according to the population studied and the diagnostic or screening approaches used. Psychological distress has also been reported to be associated with FM; however, such associations should not be interpreted as evidence that psychological distress independently causes the development of FM.⁶

Studies in the Middle East have reported relatively high estimates. A Saudi Arabian systematic review pooling heterogeneous clinical and other selected populations reported 13.4%, while a population-based study in Damascus, Syria, reported 11.8%.^7,8 These estimates are not directly interchangeable with a nationally representative estimate or a tertiary-clinic screening proportion. Differences in population selection, diagnostic criteria, sampling methods, and assessment procedures may contribute to regional variations.

To our knowledge, no previous study has evaluated fibromyalgia screening positivity among patients attending a tertiary chronic pain service in Oman. Therefore, the primary objective of this study was to determine the proportion of patients attending a tertiary pain clinic at the Royal Hospital in Muscat who screened positive using the FiRST and to identify associated sociodemographic factors.

Methods

Study Design and Setting

This descriptive cross-sectional study was conducted at the Chronic Pain Medicine Service of a tertiary center in Muscat, Oman, from January 2023 to January 2025. The study was conducted in accordance with the Declaration of Helsinki and was formally approved by the Royal Hospital Institutional Ethics Committee (approval no. SRC#26708, Muscat, Oman).

Participants and Data Collection

Adults aged ≥18 years with chronic pain, defined as pain lasting ≥3 months, were eligible for participation. Recruitment was voluntary, and written informed consent was obtained. Data collection comprised the FiRST questionnaire and sociodemographic information, including age, sex, marital status, academic level, and family relationship. Trained research assistants instructed the participants and were available during data collection to clarify linguistic nuances. Participants with incomplete questionnaires were excluded.

Patients with a pre-existing physician diagnosis of fibromyalgia were eligible for inclusion and completed the FiRST in the same manner as participants without a previous diagnosis of fibromyalgia. Previous diagnoses were not used as exclusion criteria.

Measurement Tools

The primary screening instrument was the six-item Arabic-Egyptian version of the Fibromyalgia Rapid Screening Tool (FiRST) (Table 1). The Egyptian version was developed through translation and back-translation and demonstrated an area under the curve of 0.89, a sensitivity of 86%, and a specificity of 83% at a cutoff of ≥5/6.⁹ The FiRST assesses pain distribution and characteristics, fatigue, associated abnormal sensations, and other somatic symptoms, as well as the impact on sleep and concentration. A positive FiRST result was treated as screening positivity and not as a definitive diagnosis of fibromyalgia.

Table 1.

English Items of the Fibromyalgia Rapid Screening Tool (FiRST)

Item	English Wording
1	I have pain all over my body.
2	My pain is accompanied by a continuous and very unpleasant general fatigue.
3	My pain feels like burns, electric shocks, or cramps.
4	My pain is accompanied by other abnormal sensations such as tingling, pins and needles, or numbness throughout my body.
5	My pain is accompanied by other health problems such as digestive problems, urinary problems, headaches, or restless legs.
6	My pain has a significant impact on my life, particularly on my sleep and my ability to concentrate, making me feel slower generally.

Note: FiRST is a six-item screening tool; a score of ≥5/6 was considered screening-positive in this study.

Family relationships were recorded as stable or unstable, separately from marital status in sociodemographic information. No validated scale or detailed operational threshold for these categories was used. Consequently, this variable was interpreted as a broadly recorded family relationship category rather than a validated measure of family functioning.

Statistical Analysis

Statistical analyses were performed using SPSS version 28.0 (IBM Corp., Armonk, NY, USA) and R software. Descriptive statistics were used to summarize participant characteristics, with categorical variables presented as frequencies and percentages. The proportion of participants who screened positive for fibromyalgia was estimated using a 95% confidence interval.

Bivariate analyses were performed to assess the crude association between each sociodemographic or clinical characteristic and fibromyalgia screening positivity. Pearson’s chi-square test was used for categorical variables. Crude odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated for each category relative to the prespecified reference category.

Variables demonstrating a potential association with the outcome in bivariate analyses (P<0.20), together with variables considered clinically relevant a priori, were included in multivariable logistic regression. Age group, sex, marital status, academic level, and family relationships were included in the final model. Adjusted ORs with 95% CIs were reported. Statistical significance was defined as a two-sided P<0.05.

Individual FiRST items were not entered as independent variables because they contribute directly to the definition of the screening outcome, which could introduce circularity and incorporation bias. Therefore, the final outcome was based on the overall FiRST screening status rather than its individual components.

The initial sample size was calculated using nMaster 2.0. Assuming an expected prevalence of 10%, an absolute precision of 2.5 percentage points, and a 95% confidence level, the calculated minimum was 553. The final sample comprised 401 participants. At the observed screening proportion of 42.4%, the exact 95% CI was 37.5–47.4%, corresponding to approximately ±4.9 percentage points. This precision reflects both the final sample size and the higher observed proportion.

Results

The final analysis included 401 patients with chronic pain. The cohort was predominantly female (285/401, 71.1%), and most participants were married (317/401, 79.1%). The largest age group was 40–59 years (214/401, 53.4%), followed by 18–39 years (111/401, 27.7%) and ≥60 years (76/401, 19.0%). Most participants had stable family relationships recorded (365/401, 91.0%). The participant characteristics are shown in Table 2.

Table 2.

Sociodemographic Characteristics of the Study Population (N=401)

Variable	Category	n	%
Academic level	High school or below	236	58.9
	Post-secondary	73	18.2
	Bachelor’s degree	74	18.5
	Postgraduate	18	4.5
Marital status	Married	317	79.1
	Single	40	10.0
	Divorced	21	5.2
	Widowed	23	5.7
Age group (years)	18–39	111	27.7
	40–59	214	53.4
	≥60	76	19.0
Sex	Male	116	28.9
	Female	285	71.1
Family relationship	Stable	365	91.0
	Unstable	36	9.0

Notes: Descriptive marital-status frequencies are shown separately as recorded in the frequency table Divorced and widowed participants were combined for the crude and multivariate analyses. Percentages may not sum to 100 because of rounding.

Of the 401 participants, 170 (42.4%; exact 95% CI 37.5–47.4%) screened positive using the FiRST threshold of ≥5/6, while 231 (57.6%) screened negative (Table 3).

Table 3.

Fibromyalgia Screening Status Using the FiRST (N=401)

FiRST Screening Status	n	%
Negative (<5/6)	231	57.6
Positive (≥5/6)	170	42.4
Total	401	100.0

In crude analyses, female sex was associated with higher odds of screening positivity than male sex (OR 1.594, 95% CI 1.018–2.495; P=0.042). Participants with unstable family relationships recorded had lower crude odds than those with stable relationships (OR 0.422, 95% CI 0.193–0.923; P=0.031). Participants aged 40–59 years had lower crude odds than those aged 18–39 years, although this association was not statistically significant (OR 0.656, 95% CI 0.413–1.042; P=0.074). No overall Pearson chi-square association was statistically significant for age group, marital status, academic level, job satisfaction, economic status, or chronic disease status (Table 4).

Table 4.

Bivariate (Crude) Analysis of Factors Associated with Fibromyalgia Screening Positivity (N=401)

Variable	Category	FiRST Positive n (%)	FiRST Negative n (%)	Crude OR	95% CI	P
Age group	18–39	54 (31.8)	57 (24.7)	Ref.	—	—
	40–59	82 (48.2)	132 (57.1)	0.656	0.413–1.042	0.074
	≥60	34 (20.0)	42 (18.2)	0.854	0.476–1.535	0.599
Sex	Male	40 (23.5)	76 (32.9)	Ref.	—	—
	Female	130 (76.5)	155 (67.1)	1.594	1.018–2.495	0.042
Marital status	Married	131 (77.1)	186 (80.5)	Ref.	—	—
	Single	14 (8.2)	26 (11.3)	0.765	0.385–1.520	0.444
	Divorced/widowed	25 (14.7)	19 (8.2)	1.868	0.988–3.533	0.054
Academic level	High school or below	110 (64.7)	126 (54.5)	Ref.	—	—
	Post-secondary	25 (14.7)	48 (20.8)	0.597	0.345–1.031	0.064
	Bachelor’s degree	28 (16.5)	46 (19.9)	0.697	0.408–1.190	0.186
	Postgraduate	7 (4.1)	11 (4.8)	0.729	0.273–1.945	0.528
Job satisfaction	Satisfactory	150 (88.2)	203 (87.9)	Ref.	—	—
	Unsatisfactory	20 (11.8)	28 (12.1)	0.967	0.525–1.782	0.913
Economic situation	Satisfactory	139 (81.8)	182 (78.8)	Ref.	—	—
	Unsatisfactory	31 (18.2)	49 (21.2)	0.828	0.502–1.367	0.461
Family relationship	Stable	161 (94.7)	204 (88.3)	Ref.	—	—
	Unstable	9 (5.3)	27 (11.7)	0.422	0.193–0.923	0.031
Chronic disease	No	86 (50.6)	127 (55.0)	Ref.	—	—
	Yes	84 (49.4)	104 (45.0)	1.193	0.802–1.774	0.384

Notes: Percentages are within the screening status columns (positive n=170; negative n=231). Ref. denotes the reference category; the dash indicates that the comparison estimate is not applicable. Overall Pearson chi-square P-values were as follows: age 0.182, sex 0.041, marital status 0.091, academic level 0.219, job satisfaction 0.913, economic situation 0.461, family relationship 0.027, and chronic disease 0.384. Divorced and widowed participants were combined, consistent with the analysis.

Abbreviations: OR, odds ratio; CI, confidence interval; FiRST, Fibromyalgia Rapid Screening Tool.

In the multivariable model, female sex was associated with higher odds of screening positivity (adjusted OR 1.723, 95% CI 1.065–2.787; P=0.027). Participants aged 40–59 years had lower adjusted odds than those aged 18–39 years (adjusted OR 0.528, 95% CI: 0.317–0.879; P=0.014). For participants aged ≥60 years, the estimate was lower, but the CI included 1 (adjusted OR 0.535, 95% CI 0.273–1.049; P=0.069). Family relationships were not statistically significant after adjustment (adjusted OR 0.504, 95% CI 0.225–1.129; P=0.096). Marital status and academic level were also not statistically significant after adjustment (Table 5).

Table 5.

Multivariable Logistic Regression Analysis of Factors Associated with Fibromyalgia Screening Positivity

Variable	Category	Adjusted OR	95% CI	P
Age group	18–39	Ref.	—	—
	40–59	0.528	0.317–0.879	0.014
	≥60	0.535	0.273–1.049	0.069
Sex	Male	Ref.	—	—
	Female	1.723	1.065–2.787	0.027
Marital status	Married	Ref.	—	—
	Single	0.597	0.281–1.267	0.179
	Divorced/widowed	1.549	0.785–3.058	0.207
Academic level	High school or below	Ref.	—	—
	Post-secondary	0.591	0.328–1.064	0.080
	Bachelor’s degree	0.676	0.376–1.216	0.191
	Postgraduate	0.817	0.298–2.236	0.694
Family relationship	Stable	Ref.	—	—
	Unstable	0.504	0.225–1.129	0.096

Notes: Outcome: FiRST screening positivity (≥5/6). The model included all five variables using simultaneous entry (N=401). Ref. denotes the reference category; the dash indicates that the comparison estimate is not applicable. Divorced and widowed participants were combined into a single group. Individual FiRST items were not included as predictors because they defined outcomes.

Abbreviations: OR, odds ratio; CI, confidence interval.

Discussion

Clinic-Based Screening Positivity and Selection Bias

In this tertiary chronic pain cohort, 42.4% of participants screened positive for fibromyalgia features using the FiRST. Estimates from other hospital and specialized pain cohorts vary substantially, as do general-population estimates.^10–13 Differences in referral patterns, case mix, screening instruments, diagnostic criteria, and sampling procedures limit direct comparisons. The present findings describe this tertiary clinic cohort and should not be extrapolated to the Omani population.

The high screening-positive proportion should also be interpreted in light of selection bias. Berkson’s bias refers to the distortion of associations when selection into a clinical sample depends on multiple conditions or characteristics under study.¹⁴ In a tertiary pain service, referral may depend on pain complexity, coexisting symptoms, and prior management. Such selection can alter both the screening proportion and observed associations; however, its magnitude cannot be quantified from this study.

The distinction between screening positivity and diagnosis is particularly important. FiRST is a brief screening instrument rather than a diagnostic tool.⁹ Its symptom domains can overlap with neuropathic pain, including small-fiber neuropathy, and other disorders associated with fatigue, paresthesia, and sleep disturbance. The present study did not determine the contribution of overlapping conditions to positive screens. Therefore, the 42.4% estimate represents FiRST screening positivity and does not confirm fibromyalgia, central sensitization, or a specific central pain syndrome.

The use of Egyptian Arabic FiRST in Oman warrants consideration. An Arabic instrument with published Egyptian validation was selected, and research assistants were available to clarify linguistic nuances.⁹ Other Arabic FiRST versions have also undergone cross-cultural evaluation.¹⁵ However, these studies do not establish linguistic equivalence or measurement validity in Oman. Dialectal and cultural differences may influence the interpretation of symptom descriptions, and clarification by research assistants cannot replace formal, local validation. Future studies should evaluate this instrument in Omani populations.

Age and Sex Associations

Sex remained associated with screening positivity after the adjustment. Differences in symptom recognition, healthcare-seeking behavior, and diagnostic practices can influence the sex distribution observed in fibromyalgia research.^16,17 The current association concerns the FiRST screening status within the referred cohort and does not demonstrate a causal effect of sex.

Participants aged 40–59 years had a lower adjusted odds of screening positivity than those aged 18–39 years. The estimate for participants aged ≥60 years was uncertain (adjusted OR 0.535, 95% CI 0.273–1.049; P=0.069) and did not establish an association for older adults. Referral patterns, cohort effects, symptom reporting, and measurement characteristics may contribute to the observed age pattern. Because patients with a previous physician diagnosis were eligible and completed FiRST in the same manner, exclusion based on prior diagnosis was not part of the protocol. However, the data output did not permit adjustment or stratification by prior diagnosis; therefore, its possible influence remained unresolved. These findings require confirmation in independent Omani cohorts.

Clinical and Health-System Implications

Fibromyalgia is associated with substantial functional, quality-of-life, work-related, healthcare utilization, and economic burdens.^4,5 Brief screening instruments may help identify patients who require further clinical assessment. Screening is the initial step and should be followed by the evaluation of widespread pain, associated symptoms, functional impact, and alternative or coexisting diagnoses.^18,19 Appropriate patients may then be considered for multidisciplinary care. The present data did not establish a patient’s position on the nociplastic pain spectrum or identify effective treatment.

The present study did not evaluate whether systematic screening reduces diagnostic delay, unnecessary procedures, healthcare utilization, or patient-reported outcomes. These potential benefits should therefore be considered hypotheses for future implementation studies rather than the demonstrated effects of this study.

Study Limitations

First, the final sample was smaller than planned (401 vs 553). At the observed proportion, the exact prevalence CI spanned 37.5%–47.4%, and the achieved precision depends on both sample size and the observed proportion. The calculation addressed the estimation of a proportion rather than power for each regression coefficient. Smaller subgroups and wide CIs may limit the detection of secondary associations and increase the possibility of Type II error. In particular, the ≥60-year estimate (adjusted OR 0.535, 95% CI 0.273–1.049; P=0.069) is compatible with a range of effects, including no association; non-significance should not be treated as proof of absence. Second, the cross-sectional design prevented causal inference. Third, this single tertiary referral center used voluntary rather than consecutive recruitment, allowing selection and referral bias. Fourth, FiRST cannot establish a definitive diagnosis or exclude overlapping neuropathic and other pain conditions. Fifth, the Egyptian-Arabic version was used without Oman-specific validation; linguistic and measurement bias remain possible despite research-assistant support. Sixth, family relationships lack a documented validated scale or detailed operational definition, limiting reproducibility and interpretation.

Conclusion

In this tertiary chronic pain population in Oman, 42.4% of the participants screened positive for fibromyalgia features using the FiRST. Female sex was associated with higher adjusted odds, and age 40–59 years with lower adjusted odds than age 18–39 years. The association with participants aged ≥60 years was unclear. These findings do not establish the prevalence of confirmed fibromyalgia, central sensitization, or central pain syndrome. The FiRST may serve as an initial step toward further clinical assessment. Omani validation and prospective implementation studies are needed to determine its local performance and whether systematic screening improves the patient outcomes.

Declaration of Generative AI and AI-Assisted Technologies in the Writing Process

We used Paperpal (Cactus Communications) version 2.0.19 only for language editing during the preparation of this manuscript, including the use of a grammar checker, sentence refinement, clarity, readability, and overall language quality. Paperpal had no role in the development or alteration of the scientific content, methods, statistical analyses, results, interpretations, or conclusions. All AI-assisted suggestions were reviewed and edited by the authors, who took full responsibility for the accuracy, originality, and integrity of the final manuscript. We have verified that the tool’s use is appropriate for publication by reviewing the relevant terms of use.

Disclosure

The authors declare no conflicts of interest. No funding was received for this study.