The SITE cohort study methods have been described in detail previously.19 (link) Briefly, all eligible patients seen at five academic ocular inflammation practices in the United States during the years 1979-2005 contributed to this analysis. The time period was selected based on the years covered by the National Death Index at the time of the study. Eligible patients had a non-infectious ocular inflammatory diagnosis (uveitis, scleritis, cicatrising conjunctivitis of mucous membrane pemphigoid, and other conjunctival, corneal, optic nerve, and orbital inflammatory diseases). Patients known to have HIV infection were excluded. Patients diagnosed with cancer before cohort entry were excluded from the primary within cohort survival analyses, but were included for comparisons with the United States general population (which includes people with pre-existing cancer).
The centres directly managed immunosuppression in most instances, and kept detailed records that were available for review. Data about demographic, clinical, and treatment characteristics were obtained from medical records by a structured, protocol-driven review of every visit of every patient. At four centres, all eligible patients identified were studied. At the fifth centre, because of a larger volume of patients and limited resources, a random sample of about 40% of the eligible patients were studied, oversampling subgroups likely to have received immunosuppression and patients treated early in the period of observation,19 (link) so as to maximise the information gained about immunosuppression and mortality. Reviews were done by five residency trained ophthalmologists with masters level or higher epidemiology training and one highly experienced ophthalmic technician and research coordinator. Use of immunosuppressive agents before cohort entry was noted along with the dosages of immunosuppressive agents and corticosteroids at all clinic visits. The broad range of additional data collection has been described previously.19 (link) Quality control features built into the data system required immediate correction or verification of unlikely values. Records of patients who had been seen at more than one of the participating centres were merged.
Data on mortality incidence during 1979-2005 inclusive were obtained by linkage of patient identifiers to the US National Death Index,20 (link) which provides near perfect ascertainment of mortality when US social security numbers are available (as in about 90% of our cohort).21 (link)
22 (link) Ascertainment of mortality using this approach is outstanding even based on the other identifiers we used.21 (link) Perfect matches on social security number, all names, and date of birth were accepted as matches. Possible matches with inconsistencies or missing values in one or more of these fields were manually reviewed, and adjudicated by consensus.
Causes of death were obtained using the National Death Index “plus” feature, extracted from death certificates in the same manner as for US vital statistics, which has 96% code-recode reproducibility.23 (link) Return of cancer codes (international classification of disease [ICD]-9 codes 140.0 to 208.9, 239.0 to 239.9, or ICD-10 codes C00 to C97) as the cause of death were taken as indicating a cancer death, within which return of lymphoma codes (ICD-9 codes 200.0 to 202.9 or ICD-10 codes C81.0 to C85.9) were taken as indicating a lymphoma death.
The study was approved by the participating centres’ institutional review boards, each of which approved waiver of consent for this retrospective study, and also was approved by the National Death Index review board. The study was conducted in compliance with the Declaration of Helsinki.
The centres directly managed immunosuppression in most instances, and kept detailed records that were available for review. Data about demographic, clinical, and treatment characteristics were obtained from medical records by a structured, protocol-driven review of every visit of every patient. At four centres, all eligible patients identified were studied. At the fifth centre, because of a larger volume of patients and limited resources, a random sample of about 40% of the eligible patients were studied, oversampling subgroups likely to have received immunosuppression and patients treated early in the period of observation,19 (link) so as to maximise the information gained about immunosuppression and mortality. Reviews were done by five residency trained ophthalmologists with masters level or higher epidemiology training and one highly experienced ophthalmic technician and research coordinator. Use of immunosuppressive agents before cohort entry was noted along with the dosages of immunosuppressive agents and corticosteroids at all clinic visits. The broad range of additional data collection has been described previously.19 (link) Quality control features built into the data system required immediate correction or verification of unlikely values. Records of patients who had been seen at more than one of the participating centres were merged.
Data on mortality incidence during 1979-2005 inclusive were obtained by linkage of patient identifiers to the US National Death Index,20 (link) which provides near perfect ascertainment of mortality when US social security numbers are available (as in about 90% of our cohort).21 (link)
22 (link) Ascertainment of mortality using this approach is outstanding even based on the other identifiers we used.21 (link) Perfect matches on social security number, all names, and date of birth were accepted as matches. Possible matches with inconsistencies or missing values in one or more of these fields were manually reviewed, and adjudicated by consensus.
Causes of death were obtained using the National Death Index “plus” feature, extracted from death certificates in the same manner as for US vital statistics, which has 96% code-recode reproducibility.23 (link) Return of cancer codes (international classification of disease [ICD]-9 codes 140.0 to 208.9, 239.0 to 239.9, or ICD-10 codes C00 to C97) as the cause of death were taken as indicating a cancer death, within which return of lymphoma codes (ICD-9 codes 200.0 to 202.9 or ICD-10 codes C81.0 to C85.9) were taken as indicating a lymphoma death.
The study was approved by the participating centres’ institutional review boards, each of which approved waiver of consent for this retrospective study, and also was approved by the National Death Index review board. The study was conducted in compliance with the Declaration of Helsinki.
