Chronic headache that occurs for more than 15 or more days per month or may extend for at least 3 months. It is one of the major causes of pain and disability. Certain factors like that of demographic, clinical, psychological, and social factors might affect the prognosis and treatment of people with a chronic headache.

This study was designed to identify predictors of prognosis and trial outcomes in prospective studies of people with a chronic headache.

The systematic review of published literature in peer-reviewed journals was done. This included (1) randomized controlled trials (RCTs) which had interventions for a chronic headache that reported subgroup analyses and (2) prospective cohort studies, published in English, since 1980. Participants involved adults having a chronic headache (including a chronic headache, chronic migraine, and chronic tension-type headache with or without medication overuse headache). Key databases were searched by using free text and MeSH terms. Two reviewers independently extracted data and assessed the methodologic quality of studies and overall quality of evidence identified using appropriate published checklists.

During the study 16,556 titles were identified, 663 duplicates removed, and 199 articles were reviewed, from which 27 were included in the review. Those included 17 prospective cohorts and 10 RCTs with subgroup analyses reported. The moderate-quality evidence revealed that depression, anxiety, poor sleep and stress, medication overuse, and poor self-efficacy for managing headaches are potential prognostic factors for poor prognosis and unfavourable outcomes from preventive treatment in a chronic headache. The evidence was inconclusive about treatment expectations, age, age at onset, body mass index, employment, and several headache features.

So the study estimated that numerous potential predictors of poor prognosis and worse outcome post intervention in people with a chronic headache. The majority of these are modifiable. The findings also assessed the need for more longitudinal high-quality research of prognostic factors in a chronic headache.