Study Protocol, Sample Characteristics, and Loss to Follow-Up: The OPPERA Prospective Cohort Study

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• 作者：Eric Bair ; Naomi C. Brownstein ; Richard Ohrbach ; Joel D. Greenspan ; Ronald Dubner ; Roger B. Fillingim ; William Maixner ; Shad B. Smith ; Luda Diatchenko ; Yoly Gonzalez ; Sharon M. Gordon ; Pei-Feng Lim ; Margarete Ribeiro-Dasilva ; Dawn Dampier ; Charles Knott ; Gary D. Slade
• 关键词：Temporomandibular disorder ; cohort studies ; population statistics ; epidemiologic methods ; proportional hazards models
• 刊名：The Journal of Pain
• 出版年：December, 2013
• 年：2013
• 卷：14
• 期：12_supp_S
• 页码：T2-T19
• 全文大小：1263 K

文摘

When studying incidence of pain conditions such as temporomandibular disorder (TMD), repeated monitoring is needed in prospective cohort studies. However, monitoring methods usually have limitations and, over a period of years, some loss to follow-up is inevitable. The OPPERA prospective cohort study of first-onset TMD screened for symptoms using quarterly questionnaires and examined symptomatic participants to definitively ascertain TMD incidence. During the median 2.8-year observation period, 16% of the 3,263 enrollees completed no follow-up questionnaires, others provided incomplete follow-up, and examinations were not conducted for one third of symptomatic episodes. Although screening methods and examinations were found to have excellent reliability and validity, they were not perfect. Loss to follow-up varied according to some putative TMD risk factors, although multiple imputation to correct the problem suggested that bias was minimal. A second method of multiple imputation that evaluated bias associated with omitted and dubious examinations revealed a slight underestimate of incidence and some small biases in hazard ratios used to quantify effects of risk factors. Although 鈥渂ottom line鈥?statistical conclusions were not affected, multiply-imputed estimates should be considered when evaluating the large number of risk factors under investigation in the OPPERA study.

Perspective

These findings support the validity of the OPPERA prospective cohort study for the purpose of investigating the etiology of first-onset TMD, providing the foundation for other papers investigating risk factors hypothesized in the OPPERA project.