Rybicki B A, Johnson C C, Gorell J M
Department of Research, Henry Ford Hospital and Health Sciences Center, Detroit, Mich., USA.
Neuroepidemiology. 1995;14(2):72-81. doi: 10.1159/000109781.
Although patients with Parkinson's disease (PD) are often treated by neurologists, most are first diagnosed by a primary care physician. Epidemiologic studies which use PD cases from only neurology clinics may be subject to referral bias due to differential case selection in the referral process. To study this methodological issue, a historical cohort study of all outpatients with PD diagnosed by a non-neurologist from January 1, 1988 to June 1, 1992 at the Henry Ford Health System was conducted. This health system has specialty and primary care outpatient clinics located at the main facility in Detroit, Mich. and throughout the metropolitan area. The analysis included those who had at least one outpatient visit during the follow-up period from January 1, 1988 to June 30, 1993 (n = 588), of whom 183 (31.1%) were referred to a neurologist. The univariate analysis resulted in crude risk ratios for referral of 2.14 [95% confidence interval (CI) = 1.56-2.93] for age less than 70, 2.11 (95% CI = 1.57-2.84) for male sex, 1.64 (95% CI = 1.17-2.32) for nonwhite race, 2.48 (95% CI = 1.77-3.47) for private health insurance, 1.79 (95% CI = 1.32-2.43) for being married, 1.44 (95% CI = 1.08-1.92) for 10 or more health care visits per year and 2.27 (95% CI = 1.66-3.11) for having the initial visit for PD at the main Detroit clinic. In a Cox proportional hazards model which included all study variables, race and marital status were no longer statistically significant (p < 0.05), and no risk estimates were greater than 2.0. In summary, patients referred to neurologists in this study were more likely younger, male, to have private health insurance, frequent users of health care and to use hospital-based clinics for their primary health care. We suggest that future case-control studies of PD avoid potential referral bias by not using a study population comprised solely of patients referred to a neurology clinic or design studies which can estimate the potential effect of this bias.
尽管帕金森病（PD）患者通常由神经科医生治疗，但大多数患者最初是由初级保健医生诊断的。仅使用神经科诊所的帕金森病病例的流行病学研究可能会因转诊过程中病例选择的差异而存在转诊偏倚。为了研究这个方法学问题，对1988年1月1日至1992年6月1日在亨利福特健康系统由非神经科医生诊断的所有帕金森病门诊患者进行了一项历史性队列研究。该健康系统在密歇根州底特律的主要设施以及整个大都市地区设有专科和初级保健门诊诊所。分析包括在1988年1月1日至1993年6月30日的随访期间至少有一次门诊就诊的患者（n = 588），其中183人（31.1%）被转诊至神经科医生处。单因素分析得出，年龄小于70岁的转诊粗风险比为2.14 [95%置信区间（CI）= 1.56 - 2.93]，男性为2.11（95% CI = 1.57 - 2.84），非白人种族为1.64（95% CI = 1.17 - 2.32），拥有私人医疗保险为2.48（95% CI = 1.77 - 3.47），已婚为1.79（95% CI = 1.32 - 2.43），每年就诊10次或更多次为1.44（95% CI = 1.08 - 1.92），在底特律主要诊所首次就诊为帕金森病为2.27（95% CI = 1.66 - 3.11）。在包含所有研究变量的Cox比例风险模型中，种族和婚姻状况不再具有统计学意义（p < 0.05），且没有风险估计值大于2.0。总之，本研究中转诊至神经科医生处的患者更可能较年轻、为男性、拥有私人医疗保险、频繁使用医疗保健服务且在医院门诊诊所接受初级医疗保健。我们建议，未来帕金森病的病例对照研究应避免潜在的转诊偏倚，方法是不使用仅由转诊至神经科诊所的患者组成的研究人群，或设计能够估计这种偏倚潜在影响的研究。
