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The following is a summary of “Chronobiological variables predict non-response to serotonin and noradrenaline reuptake inhibitors in fibromyalgia: a cross-sectional study,” published in the July 2024 issue of Rheumatology by Krupa et al.

Existing research links chronotype, circadian rhythms, sleep quality, and fibromyalgia (FM) symptoms but does not explore how the factors affect pharmacotherapy efficacy.

Researchers conducted a retrospective study investigating chronotypes, circadian rhythms, sleep-wake cycles, and sleep quality in patients with FM and the relationship with treatment response to serotonin-norepinephrine reuptake inhibitors (SNRIs).

They included 60 patients with FM, divided into 30 responders to SNRIs (FM T[+]), 30 non-responders (FM T[-]), and 30 HCs. Participants were evaluated through physician assessments and various questionnaires, including the Composite Scale of Morningness, Biological Rhythms Interview of Assessment in Neuropsychiatry, Sleep-Wake Pattern Assessment Questionnaire, Pittsburgh Sleep Quality Index, and Fibromyalgia Impact Questionnaire. The ANOVA and simple logistic regression analyses were conducted to explore the associations between chronobiological variables and SNRI response.

The result showed that patients with FM T[-] compared to FM T[+] exhibited significantly lower morning effect (11.50 vs. 14.00; P=0.04), decreased wakeability (2.27 vs. 4.03; P=0.013), and poorer overall (11.40 vs. 7.97; P=0.002) and subjective (1.70 vs. 1.17; P=0.008) sleep quality. Higher circadian rhythm disruptions (55.47 vs. 44.97; P<0.001), increased sleep disturbances (1.63 vs. 1.30; P=0.04), and greater use of sleep medication (1.80 vs. 0.70; P=0.003) were also observed. Key predictors of non-response to SNRI included morningness (OR=0.93, P=0.05), morning affect (OR=0.86, P=0.03), diurnal dysrhythmia (OR=1.14, P<0.001), wakeability (OR=0.76, P=0.015), overall sleep quality (OR=1.31, P=0.002), subjective sleep quality (OR=2.83, P=0.01), sleep disturbances (OR=2.54, P=0.043), sleep medication use (OR=1.90, P=0.003), and daytime dysfunction (OR=1.97, P=0.049).

Investigators concluded that chronobiological variables significantly differ between SNRI responders and non-responders in patients with FM, serving as predictors for treatment response.

Source: link.springer.com/article/10.1007/s00296-024-05650-0