Cervical musculoskeletal dysfunction in headache: How should it be defined?

Neck pain commonly accompanies migraine and tension-type headache, but the literature is divided on whether this neck pain is a headache symptom or is associated with cervical musculoskeletal dysfunction. Clarification is essential for hypotheses on the pathogenesis of these headaches and their variants and for decisions on suitability of local neck treatments, both from research and clinical practice perspectives. Reasons for disparate findings could relate to participant selection in headache studies and/or the bases on which decisions on the presence of cervical musculoskeletal dysfunction are reached. Propositions towards gaining a clearer picture of migraine and tension-type headache related neck pain include first, stricter inclusion criteria and reporting of headache characteristics of study participants. Second, reliance on pain sensitivity or the presence of neck tenderness/trigger points as measures be discarded, as they are not uniquely tied to a musculoskeletal disorder. Instead, place reliance on tests of musculoskeletal (dys)function. Third, the values and interpretation of single measures or tests of impairment/dysfunctions can be non-informative and do not reflect the presentation of cervical musculoskeletal disorders. Rather, a typical presentation includes at a fundamental level, interrelated changes in cervical movement, segmental joint and muscle function. We advocate that these measures be adopted as the core set of related measures to define cervical musculoskeletal dysfunction in headache. This does not deter inclusion of other measures of interest or qualification

Migraine day frequency in migraine prevention: longitudinal modelling approaches

Background Health economic models are critical tools to inform reimbursement agencies on health care interventions. Many clinical trials report outcomes using the frequency of an event over a set period of time, for example, the primary efficacy outcome in most clinical trials of migraine prevention is mean change in the frequency of migraine days (MDs) per 28 days (monthly MDs [MMD]) relative to baseline for active treatment versus placebo. Using these cohort-level endpoints in economic models, accounting for variation among patients is challenging. In this analysis, parametric models of change in MMD for migraine preventives were assessed using data from erenumab clinical studies. Methods MMD observations from the double-blind phases of two studies of erenumab were used: one in episodic migraine (EM) (NCT02456740) and one in chronic migraine (CM) (NCT02066415). For each trial, two longitudinal regression models were fitted: negative binomial and beta binomial. For a thorough comparison we also present the fitting from the standard multilevel Poisson and the zero inflated negative binomial. Results Using the erenumab study data, both the negative binomial and beta-binomial models provided unbiased estimates relative to observed trial data with well-fitting distribution at various time points. Conclusions This proposed methodology, which has not been previously applied in migraine, has shown that these models may be suitable for estimating MMD frequency. Modelling MMD using negative binomial and beta-binomial distributions can be advantageous because these models can capture intra- and inter-patient variability so that trial observations can be modelled parametrically for the purposes of economic evaluation of migraine prevention. Such models have implications for use in a wide range of disease areas when assessing repeated measured utility values