H erpes zoster (HZ), or shingles, is usually considered a once-in-a-lifetime experience, with HZ recurrences thought to be limited to immunocompromised individuals. The plausibility, actual occurrence, and frequency of recurrent HZ have been debated. [1][2][3][4][5] Studies of HZ recurrence often focus on special populations with hematologic malignancies or exposure to chemotherapeutic or immunotoxic agents like arsenic, [6][7][8][9] or they are population studies with small numbers of cases or short follow-up periods. [10][11][12][13][14][15][16] This study assessed the rate of HZ recurrence with up to 12 years of follow-up in a population-based cohort of 1669 persons with a confirmed previous episode of HZ between January 1, 1996, and December 31, 2001. Like the index episodes, HZ recurrences were required to meet predefined diagnostic criteria of dermatomal rash and pain. [17][18][19][20] These data should provide health care professionals, insurers, and policy makers a more robust basis for practice, insurance, and policy decisions regarding prevention and treatment of HZ recurrences.
PATIENTS AND METHODSWe reviewed the medical records of a community population-based cohort of people with a confirmed episode of HZ followed up for recurrence for as long as 12 years after the index episode. Recurrence rates were expressed by time from the index episode to the first recurrence and stratified by sex, age, and immune status (immunocompromised or immunocompetent) as assessed at the time of the initial or index episode of HZ. Data from the Rochester Epidemiology Project 22,23 made it possible to identify all care provided to each of these individuals by any outpatient or inpatient health care facility within the county during the follow-up period.Identification and confirmation of the index episodes of HZ have been described previously.17 Briefly summarized, the original incidence study looked at the medical records of all residents of Olmsted County, Minnesota, aged 22 years or older who, according to administrative data, presented to any health care site with an acute HZ episode between January 1, 1996, and December 31, 2001. Using detailed medical record review, we confirmed the index HZ case and collected data on HZ complications, treatment, and immune status. Any person with an administrative HZ code before the period of interest (January 1, 1996, through December 31, 2001) was excluded from the cohort in an effort to assess rates of first HZ occurrence.For this recurrence study, the medical records of all individuals with a confirmed HZ episode in the initial incidence study were reviewed from the date of their index HZ episode through December 31, 2007 (ie, a 6-to 12-year follow-up) to identify HZ recurrences. All medical records of all Olmsted County, Minnesota, health care facilities were reviewed to identify any recurrences for each individual in
