This cross-sectional study included 76 patients having glaucoma with poor clinic follow-up and 76 patients having glaucoma with good clinic follow-up who were recruited during a 6-month period in 2008–2009 as part of a case-control study at the San Francisco General Hospital (SFGH) glaucoma clinic. The clinic is situated at an urban publicly owned county hospital that provides comprehensive health care services and acts as a safety net for San Francisco's poor, uninsured, homeless, and immigrant populations. The clinic is staffed by resident and attending physicians from the University of California, San Francisco.
All subjects were classified either as cases (those with poor follow-up) or controls (those with good follow-up). This classification was based on adherence to follow-up regimens generally recommended for patients at the SFGH depending primarily on disease severity and control (
Table 1). For all subjects, glaucoma follow-up visits at the SFGH during the period 12 to 18 months before the commencement of the study were ascertained from documentation in their medical records. Subjects deemed to have good follow-up were those who attended follow-up visits within a certain maximum interval between visits as advised by their ophthalmologist. Disease severity for each subject was assessed by a senior glaucoma specialist (J-YH, SL) according to the American Academy of Ophthalmology Preferred Practice Pattern guidelines for primary open-angle glaucoma
23 and was based on the subject's most recent ophthalmological examination, including optic nerve and visual field characteristics.
Subject eligibility criteria included the following: (1) establishment of care at the SFGH glaucoma clinic at least 1 year before study commencement as ascertained by review of the medical record, (2) age 40 years or older, and (3) a diagnosis of primary open-angle glaucoma, angle-closure glaucoma, normal tension glaucoma, pigmentary and/or exfoliative glaucoma, or ocular hypertension. All eligible patients attending follow-up visits in the glaucoma clinic were approached regarding enrollment in the study whenever a member of the multilingual research team (BWL, YM, MTD, AAK) was available to conduct oral questionnaires.
After obtaining informed consent, subjects were asked whether they were proficient in English. The standardized questionnaires were administered orally in the subject's preferred language (English, Spanish, Mandarin, Cantonese, Vietnamese, or Tagalog) by a member of the multilingual research team. Data were collected on race and ethnicity, as well as on other factors such as transportation to the clinic, monetary cost of medications and follow-up clinic visits, medication use, knowledge about glaucoma, and perceptions regarding the difficulty and importance of attending glaucoma follow-up examinations. All subjects were then asked specifically whether any of 16 potential barriers posed “significant barriers” to attending glaucoma follow-up during the past year. They were also asked to cite any additional barriers, as well as the single most important barrier, where applicable.
Before formal commencement of the study, a pilot study was conducted with 14 patients meeting the eligibility criteria to validate the questionnaire, develop coding classifications, and test the questionnaire's feasibility and acceptability. The study protocol was approved by the institutional review boards of the collaborating institutions (the Stanford University School of Medicine, the SFGH, and the University of California, San Francisco). This research project adhered to the tenets of the Declaration of Helsinki and maintained Health Insurance Portability and Accountability Act of 1996 compliance at all times.
Statistical analysis was performed using a commercially available software package (SPSS 18.0; SPSS, Chicago, IL). The prevalence of various barriers to follow-up was calculated for the aggregate study population and was also stratified by race as part of a prospectively planned analysis. The χ2 test was used to determine whether certain barriers disproportionately affected specific ethnic groups.