Improving quality in population surveys of headache prevalence, burden and cost: key methodological considerations

Abstract

Population-based studies of headache disorders are important. They inform needs assessment and underpin service policy for a set of disorders that are a public-health priority. On the one hand, our knowledge of the global burden of headache is incomplete, with major geographical gaps; on the other, methodological differences and variable quality are notable among published studies of headache prevalence, burden and cost.The purpose here was to start the process of developing standardized and better methodology in these studies. An expert consensus group was assembled to identify the key methodological issues, and areas where studies might fail. Members had competence and practical experience in headache epidemiology or epidemiology in general, and were drawn from all WHO world regions. We reviewed the relevant literature, and supplemented the knowledge gathered from this exercise with experience gained from recent Global Campaign population-based studies, not all yet published. We extracted methodological themes and identified issues within them that were of key importance.We found wide variations in methodology. The themes within which methodological shortcomings had adverse impact on quality were the following: study design; selection and/or definition of population of interest; sampling and bias avoidance; sample size estimation; access to selected subjects (managing and reporting non-participation); case definition (including diagnosis and timeframe); case ascertainment (including diagnostic validation of questionnaires); burden estimation; reporting (methods and results). These are discussed.

The Prevalence and Impact of Headache in Brazil

“…They are the main reason for patient visits to neurologists' offices, and it is one of the most frequent symptoms reported to primary care physicians . Epidemiological studies are important to understand the scope and scale of headache in specific areas or countries, in order to better know its causes, mechanisms, natural history and comorbidities, to estimate its burden to individuals and to societies, and to help health care providers and government authorities to appropriately spend their resources, accepting headache disorders as a public health priority …”

“…Merikangas, in a review of recent publications of migraine prevalence, utilizing exclusively the International Classification of Headache Disorders‐II criteria, found an aggregated rate of 11.5%. A group of experts, led by Lifting the Burden, a nongovernmental organization conducting the Global Campaign Against Headache, has published recently some guidelines in an attempt to standardize the methodology of epidemiological studies on headache . This group highlights the crucial role of population‐based studies as a meaningful way of quantifying the headache problem, as a starting point for public health care planning.…”

“…This group highlights the crucial role of population‐based studies as a meaningful way of quantifying the headache problem, as a starting point for public health care planning. These authors emphasize the importance of knowing the epidemiology of headache in large and populated countries, such as Brazil, China, India, and Russia, even though this is a challenging task …”

The methodology of population surveys of headache prevalence, burden and cost: Principles and recommendations from the Global Campaign against Headache

“…Many factors that influence quality have been noted to be inadequately addressed in past studies [3]. These, and others of potential importance, are made the subject of recommendations accompanied by detailed explanatory commentary.…”

An Intelligent Systems Approach to Primary Headache Diagnosis

“…Such conditions are currently dichotomised into two broad categories, primary (benign), and secondary (serious), where the former occurrences are relatively common and the latter constitute only around 10% of all known cases [7]. Although epidemiological and impact studies of headache remain incomplete [8], it is indicated that the combined prevalence of headache conditions is set at around 50% of the global population, rendering an economic impact estimated to be £500 million per annum in the UK and between $5.6 and $17.2 billion in the United States alone [9]. Correspondingly, headache conditions account for one of the most common complaints within primary and neurological care settings, with a significant proportion of sufferers choosing not to seek medical attention [10] and therefore remaining unreflected in the estimates.…”