Objective. To evaluate the quality of the methods and reporting of published studies that validate administrative database algorithms for rheumatic disease case ascertainment.

Methods. We systematically searched MEDLINE, Embase, and the reference lists of articles published from 1980 to 2011. We included studies that validated administrative data algorithms for rheumatic disease case ascertainment using medical record or patient-reported diagnoses as the reference standard. Each study was evaluated using published standards for the reporting and quality assessment of diagnostic accuracy, which informed the development of a methodologic framework to help critically appraise and guide research in this area.

Results. Twenty-three studies met the inclusion criteria. Administrative database algorithms to identify cases were most frequently validated against diagnoses in medical records (83%). Almost two-thirds of the studies (61%) used diagnosis codes in administrative data to identify potential cases and then reviewed medical records to confirm the diagnoses. The remaining studies did the reverse, identifying patients using a reference standard and then testing algorithms to identify cases in administrative data. Many authors (61%) described the patient population, but few (26%) reported key measures of diagnostic accuracy (sensitivity, specificity, and positive and negative predictive values). Only one-third of studies reported disease prevalence in the validation study sample.

Conclusion. The methods used in administrative data validation studies of rheumatic diseases are highly variable. Few studies reported key measures of diagnostic accuracy despite their importance for drawing conclusions about the validity of administrative database algorithms. We developed a methodologic framework and recommendations for validation study conduct and reporting.

Objective: To determine the validity of the diagnostic algorithms for osteoporosis and fractures in administrative data.

Study Design and Setting: A systematic search was conducted to identify studies that reported the validity of a diagnostic algorithm for osteoporosis and/or fractures using administrative data.

Results: Twelve studies were reviewed.The validity of the diagnosis of osteoporosis in administrative data was fair when at least 3years of data from hospital and physician visit claims were used (area under the receiver operating characteristic [ROC] curve [AUC] 5 0.70) or when pharmacy data were used (with or without the use of hospital and physician visit claims data, AUC O 0.70). Nonetheless, the positive predictive values (PPVs) were low (!0.60). There was good evidence to support the use of hospital data to identify hip fractures (sensitivity: 69e97%; PPV: 63e96%) and the addition of physician claims diagnostic and procedural codes to hospitalization diagnostic codes improved these characteristics (sensitivity: 83e97%; PPV: 86e98%). Vertebral fractures were difficult to identify using administrative data. There was some evidence to support the use of administrative data to define other fractures that do not require hospitalization.

Conclusions: Administrative data can be used to identify hip fractures. Existing diagnostic algorithms to identify osteoporosis and vertebral fractures in administrative data are suboptimal.

Objective. To assess risk and risk factors for serious infections in seniors with rheumatoid arthritis (RA) using a case–control study nested within an RA cohort.

Methods. We assembled a retrospective RA cohort age >66 years from Ontario health administrative data across 1992–2010. Nested case– control analyses were done, comparing RA patients with a primary diagnosis of infection (based on hospital or emergency department records) to matched RA controls. We assessed independent effects of drugs, adjusting for demographics, comorbidity, and markers of RA severity.

Results. A total of 86,039 seniors with RA experienced 20,575 infections, for a rate of 46.4 events/1,000 person-years. The most frequently occurring events included respiratory infections, herpes zoster, and skin/soft tissue infections. Factors associated with infection included higher comorbidity, rural residence, markers of disease severity, and history of previous infection. In addition, anti–tumor necrosis factor agents and disease-modifying antirheumatic drugs were associated with a several-fold increase in infections, with an adjusted odds ratio (OR) ranging from 1.2–3.5. The drug category with the greatest effect estimate was glucocorticoids, which exhibited a clear dose response with an OR ranging from 4.0 at low doses to 7.6 at high doses.

Conclusion. Seniors with RA have significant morbidity related to serious infections, which exceeds previous reports among younger RA populations. Rural residence, higher comorbidity, markers of disease severity, and previous infection were associated with serious infections in seniors with RA. Our results emphasize that many RA drugs may increase the risk of infection, but glucocorticoids appear to confer a particular risk.

Objective. To estimate the population-based prevalence of systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) in Alberta, Canada, stratified by First Nations status.

Methods. Physician billing claims and hospitalization data for the province of Alberta (1994–2007) were used to ascertain cases of SLE and SSc using 3 case definitions. A latent class Bayesian hierarchical regression model was employed to account for the imperfect sensitivity and specificity of billing and hospitalization data in case ascertainment. We accounted for demographic factors, estimating prevalence rates for the First Nations and non–First Nations popula- tions by sex, age group, and location of residence (urban/rural).

Results. Our model estimated the prevalence of SLE in Alberta to be 27.3 cases per 10,000 females (95% credible interval [95% CrI] 25.9 –28.8) and 3.2 cases per 10,000 males (95% CrI 2.6 –3.8). The overall prevalence of SSc in Alberta was 5.8 cases per 10,000 females (95% CrI 5.1–6.5) and 1.0 case per 10,000 males (95% CrI 0.7–1.4). First Nations females over 45 years of age had twice the prevalence of either SLE or SSc relative to non–First Nations females. There was also a trend toward higher overall SLE prevalence in urban dwellers, and higher overall SSc prevalence in rural residents.

Conclusion. First Nations females older than 45 years of age have an increased prevalence of either SLE or SSc. This may reflect a true predominance of autoimmune rheumatic diseases in this demographic, or may indicate systematic differences in health care delivery.

Abstract

Background: Population-based administrative data have been used to study osteoporosis-related fracture risk factors and outcomes, but there has been limited research about the validity of these data for ascertaining fracture cases. The objectives of this study were to: (a) compare fracture incidence estimates from administrative data with estimates from population-based clinically-validated data, and (b) test for differences in incidence estimates from multiple administrative data case definitions.

Methods: Thirty-five case definitions for incident fractures of the hip, wrist, humerus, and clinical vertebrae were constructed using diagnosis codes in hospital data and diagnosis and service codes in physician billing data from Manitoba, Canada. Clinically-validated fractures were identified from the Canadian Multicentre Osteoporosis Study (CaMos). Generalized linear models were used to test for differences in incidence estimates.

Results: For hip fracture, sex-specific differences were observed in the magnitude of under- and over-ascertainment of administrative data case definitions when compared with CaMos data. The length of the fracture-free period to ascertain incident cases had a variable effect on over-ascertainment across fracture sites, as did the use of imaging, fixation, or repair service codes. Case definitions based on hospital data resulted in under-ascertainment of incident clinical vertebral fractures. There were no significant differences in trend estimates for wrist, humerus, and clinical vertebral case definitions.

Conclusions: The validity of administrative data for estimating fracture incidence depends on the site and features of the case definition.

The Manitoba Centre for Health Policy (MCHP) is located within the Department of Community Health Sciences, Faculty of Medicine, University of Manitoba. The mission of MCHP is to provide accurate and timely information to health care decision-makers, analysts and providers, so they can offer services which are effective and efficient in maintaining and improving the health of Manitobans. Our researchers rely upon the unique Population Health Research Data Repository to describe and explain pat- terns of care and profiles of illness, and to explore other factors that influence health, including income, education, employment and social status. This Repository is unique in terms of its comprehensiveness, degree of integration, and orientation around an anonymized population registry.

Members of MCHP consult extensively with government officials, health care administrators, and clinicians to develop a research agenda that is topi- cal and relevant. This strength along with its rigorous academic standards enable MCHP to contribute to the health policy process. MCHP under- takes several major research projects, such as this one, every year under con- tract to Manitoba Health. In addition, our researchers secure external fund- ing by competing for other research grants. We are widely published and internationally recognized. Further, our researchers collaborate with a number of highly respected scientists from Canada, the U.S. and Europe.

We thank the University of Manitoba, Faculty of Medicine, Health Research Ethics Board for their review of this project. The Manitoba Centre for Health Policy complies with all legislative acts and regulations governing the protection and use of sensitive information. We implement strict policies and procedures to protect the privacy and security of anonymized data used to produce this report and we keep the provincial Health Information Privacy Committee informed of all work undertaken for Manitoba Health.

Rheumatoid arthritis (RA) is often characterized by the burden of swollen joints, pain, and de- creased physical function, but less understood are the many manifestations of additional health conditions that are associated with RA and its treatments. First brought to light with observations of increased mortality in RA, studies noted the increased rates of cardiovascular and infection events. The chronic, debilitating, autoimmune nature of RA affects the patient directly or indi rectly in almost all organ systems, from cardiovascular problems and infections to depression and gastrointestinal ulcers. On average, the established RA patient has two or more comorbid conditions. It should be the responsibility of the rheumatologist to take these and the risk of additional conditions into account when treating the patient. This chapter reviews important comorbidities in patients with RA, their prevalence, and their relation to RA.

Key words: anti-TNF therapy; cardiovascular disease; comorbid condition; comorbidity index; comorbidity; infection; malignancy; outcomes; rheumatoid arthritis.

To the Editors:
I read with great interest the article by Pons-Estel et al, recently published in Arthritis Care & Research, on hy- droxychloroquine (HCQ) use and its effect on renal dam- age in persons with underlying lupus renal disease (1). The authors found that HCQ use (classified as ever used versus never used) by persons with renal disease, but not yet any renal damage as defined by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index renal domain, reduced the risk of subsequent renal damage with an adjusted hazard ratio (HR) of 0.29. As presented, this article has 2 major limitations in study design that make this finding ques- tionable.

ABSTRACT

Objectives: The introduction of biological therapies for the treatment of rheumatic diseases has drawn attention to the limitations of traditional means of assessing drug safety. Consequently, a series of European academic biologics registers dedicated to this task have been established. Increasing reliance upon safety data generated from observational drug registers makes it important to convert the lessons learned from such registers into recommendations for rheumatologists embarking upon the establishment of future registers, or analysing and reporting from new and existing registers.

Methods: The Task Force encompassed 11 scientists from European Rheumatology drug registers. Through
an informal inventory of critical elements in the establishment of existing rheumatoid arthritis drug registers, of analytical strategies used and of limitations of their results, several ‘points to consider’—beyond established generic guidelines for observational registers/ studies but with particular relevance to biologics registers on safety in rheumatology—were assembled. For each ‘point to consider’, contextual and methodological background and examples were compiled.

Results: A set of seven points to consider was assembled for the establishment of new drug registers with a focus on purpose, population to be targeted, data collection, handling and storage as well as ethical and legal considerations. For analysis and reporting, nine points to consider were assembled (setting, participant, variable, statistical method, descriptive data, outcome data, main results, other analyses and limitations).

Conclusions: Thoughtful design and planning before
the establishment of biologics registers will increase
their sustainability, versatility and raw data quality. Harmonisation of analyses and reporting from such registers will improve interpretation of drug safety studies.