The Course of Frequent Episodic Migraine in a Large Headache Clinic Population: A 12-year Retrospective Follow-up Study

Abstract and Introduction

Abstract

Background.—Despite its high prevalence, little is known about the clinical course of migraine. Presented here are the findings of a 12-year follow-up study involving patients diagnosed at baseline with frequent episodic migraine.
Objective.—The main objectives were to determine the long-term outcome of patients with frequent episodic migraine and to identify factors predictive of a favorable vs less favorable prognosis.
Methods.—A total of 374 subjects (200 women, 174 men) were selected randomly from a total population of 2812 patients initially diagnosed before December 31, 1996, with episodic migraine and at baseline experiencing 1 to 6 attacks per month. Their subsequent migraine course was evaluated via telephone interviews conducted between 2005 and 2006.
Results.—Migraine attacks had ceased in 110 (29%) of the 374 patients (57 women and 53 men). The remaining 264 subjects continued to experience migraine attacks at follow-up, and a change in attack frequency was reported by 80% (of whom 80% reported fewer attacks). Sixty-six percent reported a change in pain intensity over time, and of these 83% reported milder pain. Only 6 subjects (6/374 = 1.6%) had developed chronic migraine.
Conclusion.—These data from a headache clinic population suggest that migraine has a favorable prognosis in most patients. Whether the findings reflect the natural history of the disorder or interval improvements in headache management remains conjectural.

Introduction

Despite its high prevalence, little is known about the prognosis and potential clinical progression of migraine.^[1–3] Whereas cross-sectional studies on migraine characteristics and epidemiology are abundant, information from longitudinal studies is scarce. Even less is known as to whether there are any factors predictive of prognosis. It is of obvious importance to the patient and physician to understand how the disorder might change over time, and during the last decade efforts have been made to learn more about the migraine's potential liability to evolve into a progressive disease with an associated risk of brain injury and, specifically, deterioration of cognitive function.^[4–10]

One of the most cited studies regarding the natural history of migraine is Bille's 40-year prospective investigation of 73 schoolchildren in Sweden.^[11] Bille found that at age 25, after 16 years of follow-up, 23% of the subjects had become migraine-free (males more often than females). At the 40-year follow-up, 46% of the studied population was migraine-free, and no gender differences were observed at that point. Further studies on the evolution of migraine in children and adolescents have demonstrated similar results; depending on the length of the observation period involved (ranging 3–10 years), migraine attacks had ceased in 15–44% of the subjects under investigation.^[12–20]

Studies involving adults also have indicated a favorable prognosis.^[21–24] For example, 2 studies in patients with migraine with aura (MwA 1.2) recruited from headache clinics (follow-up 10–20 years and 16 years, respectively) showed that migraine had ceased in 36% and 35% of subjects, respectively.^[23,25] Studies investigating the prognosis of headache generally have been published, but the authors have not distinguished between different headache types or, specifically, used the International Classification of Headache Disorders (ICHD) criteria at baseline.^[26–29]

In a few studies, attempts were made to identify possible predictive factors for a favorable or unfavorable prognosis.^{[10,18,22,24,30]} Aging, male gender, visual aura, absence of trigger factors, and late onset have been suggested as predictors of a more positive migraine prognosis.^{[14,17,18,23]}

In summary, many studies have suggested that migraine typically has a benign long-term prognosis, and it seems that migraine attacks often cease with age. In a subgroup of migraineurs, however, migraine may transform into chronic daily headache.^[6] High attack frequency and overuse of symptomatic medication are strong predictors for such "chronification," with an incidence per annum reportedly ranging between 3% and 14%.^[10,30]

The primary objective of this study was to identify those patients with episodic migraine in the Gothenburg Clinic Migraine File database who were diagnosed at the clinic more than 10 years ago and at that time had a frequency of 1–6 attacks per month, to contact a randomly selected sample of those patients and to evaluate the present status of their migraine. In particular, we sought to identify migraineurs whose attacks had ceased during the follow-up period and to determine whether there existed any variables predictive of such cessation. Secondary objectives were to identify any changes in frequency, intensity, or duration of migraine attacks, as well as to determine the incidence of progression to chronic migraine.

Headache. 2009;49(8):1144-1152. © 2009 

Cite this: The Course of Frequent Episodic Migraine in a Large Headache Clinic Population: A 12-year Retrospective Follow-up Study - Medscape - Sep 01, 2009.