Health administrative data can be a valuable tool for disease surveillance and research. Few studies have rigorously evaluated the accuracy of administrative databases for identifying rheumatoid arthritis (RA) patients. Our aim was to validate administrative data algorithms to identify RA patients in Ontario, Canada.
We performed a retrospective review of a random sample of 450 patients from 18 rheumatology clinics. Using rheumatologist-reported diagnosis as the reference standard, we tested and validated different combinations of physician billing, hospitalization, and pharmacy data.
One hundred forty-nine rheumatology patients were classified as having RA and 301 were classified as not having RA based on our reference standard definition (study RA prevalence 33%). Overall, algorithms that included physician billings had excellent sensitivity (range 94-100%). Specificity and positive predictive value (PPV) were modest to excellent and increased when algorithms included multiple physician claims or specialist claims. The addition of RA medications did not significantly improve algorithm performance. The algorithm of "(1 hospitalization RA code ever) OR (3 physician RA diagnosis codes [claims] with =1 by a specialist in a 2-year period)" had a sensitivity of 97%, specificity of 85%, PPV of 76%, and negative predictive value of 98%. Most RA patients (84%) had an RA diagnosis code present in the administrative data within ±1 year of a rheumatologist's documented diagnosis date.
We demonstrated that administrative data can be used to identify RA patients with a high degree of accuracy. RA diagnosis date and disease duration are fairly well estimated from administrative data in jurisdictions of universal health care insurance.
Poor medication-taking behaviors are important considerations in the management of hypertension.
We conducted a retrospective cohort study addressing antihypertensive drug persistence and compliance by linking 4 administrative databases and a province-wide clinical database in Ontario, Canada, to derive a cohort of elderly hypertensive patients, aged 66 years or more, who had received a new prescription for an antihypertensive agent between 1997 and 2005 to determine trends across years and associations with drug class and sociodemographic and other factors.
Our cohort consisted of 207,473 patients (58.4% were women, mean age 74.2 years, 73.1% were comorbid-free), 41,236 of whom had diabetes. Persistence and compliance increased between 1997 and 2005 (all P
Institute for Clinical Evaluative Sciences (ICES), Toronto, Ontario, Canada; Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada; University Health Network-Toronto Western Hospital Family Health Team, Toronto, Ontario, Canada. Electronic address: firstname.lastname@example.org.
The objective of this study was to examine persistence rates and factors influencing persistence for new elderly users of antihypertensive drugs.
We conducted a population-based cohort study in Ontario of adults aged 66 years or older to identify new users of antihypertensive medications between 1999 and 2010. Two-year therapy and class persistence were defined as persistence on any antihypertensive medication and persistence only on the same antihypertensive medication class, respectively.
From 1999-2010, the prevalence of antihypertensive drug use increased from 47.8%-60.5% (P
The purpose of this study was to examine whether prescribing practices for elderly individuals with diabetes and hypertension changed over the past decade.
We linked the Ontario Diabetes Database and four administrative databases in Ontario, Canada, to identify 27,822 patients >65 years of age who had diabetes and were newly treated for hypertension between 1 January 1995 and 31 December 2001. All patients were followed for 2 years after their initial antihypertensive medication prescription.
The 27,822 patients in this study (mean age 72 years, 51% men) were treated with oral hypoglycemic agents alone (n = 17,128 patients, 62%), insulin alone (n = 2,346, 8%), both oral hypoglycemic agents and insulin (n = 2,205, 8%), or diet alone (n = 6,143, 22%). Management within the first 2 years of hypertension diagnosis consisted of antihypertensive monotherapy in 20,183 patients (73%), two antihypertensive drugs in 6,207 (22%), and three or more drugs in 1,432 (5%); the most frequently chosen antihypertensive drugs were ACE inhibitors (68%), thiazides (15%), and calcium channel blockers (9%). Between 1995 and 2001, physician prescribing practices changed: the population-adjusted rates of antihypertensive drug prescribing increased by 46% (95% CI 33-55%), the proportion of initial antihypertensive prescriptions for ACE inhibitors increased from 54 to 76% (P
The aim of this study was to determine whether the incidence of type 2 diabetes differed among elderly users of four major antihypertensive drug classes.
This was a retrospective, observational cohort study of previously untreated elderly patients (aged > or = 66 years) identified as new users of an antihypertensive drug class between April 1995 and March 2000. Using a Cox proportional hazards model, the primary analysis compared diabetes incidence in users of ACE inhibitors, beta-blockers, and calcium channel blockers (CCBs), with thiazide diuretics allowed as second-line therapy. In the secondary analysis, thiazide diuretics were added as a fourth study group.
In the multivariable-adjusted primary analysis (n = 76,176), neither ACE inhibitor use (hazard ratio 0.96 [95% CI 0.84-1.1]) nor beta-blocker use (0.86 [0.74-1.0]) was associated with a statistically significant difference in type 2 diabetes incidence compared with the CCB control group. In the secondary analysis (n = 100,653), compared with CCB users, type 2 diabetes incidence was not significantly different between users of ACE inhibitors (0.97 [0.83-1.1]), beta-blockers (0.84 [0.7-1.0]), or thiazide diuretics (1.0 [0.89-1.2]).
Type 2 diabetes incidence did not significantly differ among users of the major antihypertensive drug classes in this elderly, population-based administrative cohort. These results do not support the theory that different antihypertensive drug classes are relatively more or less likely to cause diabetes.
The surveillance of heart failure (HF) is currently conducted using either survey or hospital data, which have many limitations. Because Canada is collecting medical information in administrative health data, the present study seeks to propose methods for the national surveillance of HF using linked population-based data.
Linked administrative data from 5 Canadian provinces were analyzed to estimate prevalence, incidence, and mortality rates for persons with HF between 1996/1997 and 2008/2009 using 2 case definitions: (1) 1 hospitalization with an HF diagnosis in any field (H_Any) and (2) 1 hospitalization in any field or at least 2 physician claims within a 1-year period (H_Any_2P). One hospitalization with an HF diagnosis code in the most responsible diagnosis field (H_MR) was also compared. Rates were calculated for individuals aged = 40 years.
In 2008/2009, combining the 5 provinces (approximately 82% of Canada's total population), both age-standardized HF prevalence and incidence were underestimated by 39% and 33%, respectively, with H_Any when compared with H_Any_2P. Mortality was higher in patients with H_MR compared with H_Any. The degree of underestimation varied by province and by age, with older age groups presenting the largest differences. Prevalence estimates were stable over the years, especially for the H_Any_2P case definition.
The prevalence and incidence of HF using inpatient data alone likely underestimates the population rates by at least 33%. The addition of physician claims data is likely to provide a more inclusive estimate of the burden of HF in Canada.
Institute for Clinical Evaluative Sciences (ICES), Toronto, Ontario, Canada; Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada; Toronto Western Hospital Family Health Team, University Health Network, Toronto, Ontario, Canada.
Previous validation studies assessing the use of administrative data to identify patients with epilepsy have used targeted sampling or have used a reference standard of patients in the neurologist, hospital, or emergency room setting. Therefore, the validity of using administrative data to identify patients with epilepsy in the general population has not been previously assessed. The purpose of this study was to determine the validity of using administrative data to identify patients with epilepsy in the general population.
A retrospective chart abstraction study was performed using primary care physician records from 83 physicians distributed throughout Ontario and contributing data to the Electronic Medical Record Administrative data Linked Database (EMRALD) A random sample of 7,500 adult patients, from a possible 73,014 eligible, was manually chart abstracted to identify patients who had ever had epilepsy. These patients were used as a reference standard to test a variety of administrative data algorithms.
An algorithm of three physician billing codes (separated by at least 30 days) in 2 years or one hospitalization had a sensitivity of 73.7% (95% confidence interval [CI] 64.8-82.5%), specificity of 99.8% (95% CI 99.6-99.9%), positive predictive value (PPV) of 79.5% (95% CI 71.1-88.0%), and negative predictive value (NPV) of 99.7% (95% CI 99.5-99.8%) for identifying patients who had ever had epilepsy.
The results of our study showed that administrative data can reasonably accurately identify patients who have ever had epilepsy, allowing for a "lifetime" population prevalence determination of epilepsy in Ontario and the rest of Canada with similar administrative databases. This will facilitate future studies on population level patterns and outcomes of care for patients living with epilepsy.
Angiotensin-converting enzyme (ACE) inhibitor-induced acute pancreatitis has been described in various case reports and drug surveillance databases. At present, no epidemiologic studies examining the potential association between ACE inhibitors and acute pancreatitis have been identified.
To determine whether there is an association between ACE inhibitor use and pancreatic events (acute pancreatitis, pancreatic surgery).
A retrospective cohort of Ontario residents aged >/=66 years was created using population-based administrative databases from January 1, 1994, through March 31, 2000. We compared the incidence of pancreatic events among new users of ACE inhibitors (study group), warfarin (null baseline group), and dihydropyridine calcium-channel antagonists (DCCAs; disease control group) using multivariate Cox proportional hazard models.
The primary outcome measure was hospitalization with acute pancreatitis; the secondary outcome measure was incidence of pancreatic surgery.
For acute pancreatitis, the crude incidence rates per 10,000 person-years were 9.0 for the ACE inhibitor group (n = 174,824); 7.1 for the DCCA group (n = 73,719), and 7.6 for the warfarin group (n = 40 057). Relative to warfarin users, neither ACE inhibitor users (adjusted rate ratio [aRR] = 1.35; 95% CI 0.94 to 1.93) nor DCCA users (aRR = 1.09; 95% CI 0.72 to 1.62) were at significantly higher risk of hospitalization for acute pancreatitis. For pancreatic surgery in the same population, the crude incidence rates per 10,000 person-years were 10.5 for the ACE inhibitor group, 10.6 for the DCCA group, and 10.7 for the warfarin group. Relative to subjects taking warfarin, neither ACE inhibitor users (aRR = 1.09; 95% CI 0.80 to 4.49) nor DCCA users (aRR = 1.11; 95% CI 0.79 to 1.56) were at significantly higher risk for pancreatic surgery.
The use of ACE inhibitors does not appear to be associated with significant risk of acute pancreatitis among the elderly.
Little is known regarding potential differences in antihypertensive prescribing practices at a Canadian provincial level. Our objective was to determine provincial differences in the use of antihypertensive drug therapy in Canada.
Using longitudinal drug data (IMS CompuScript database; IMS Health Canada), we examined the increase in number of prescriptions dispensed for all antihypertensive agents for each province over an 11-year period (1996-2006).
Over the 11-year study period, antihypertensive prescriptions increased by 106.2% for single-drug therapy (from 35.8% in Prince Edward Island and Newfoundland to 167.2% in British Columbia) and by 112.8% (from 22.0% in New Brunswick to 216.0% in Québec) for combination-drug therapy. Among drug classifications, angiotensin receptor blockers had the largest increase for single-drug therapy and angiotensin-converting enzyme inhibitors-diuretics for combination-drug therapy. There were marked provincial differences in the increase in total antihypertensive therapy, ranging from British Columbia, with an increase of 262%, to Prince Edward Island and Newfoundland, where the increase was 134%.
Large increases in antihypertensive prescriptions occurred in all provinces of Canada, but the provinces varied substantially in the increase in total and drug-specific classes of antihypertensive drugs. The basis for provincial differences in antihypertensive prescriptions remains unknown and is likely multifactorial but may relate in part to initial provincial variations in diagnosis, treatment, and control of hypertension, as well as individual provincial drug policies.
High blood pressure is an important and modifiable cardiovascular disease risk factor that remains under-detected and under-treated. Community-level interventions that address high blood pressure and other modifiable risk factors are a promising strategy to improve cardiovascular health in populations. The present study is a community cluster-randomised trial testing the effectiveness of CHAP (Cardiovascular Health Awareness Program) on the cardiovascular health of older adults.
Thirty-nine mid-sized communities in Ontario, Canada were stratified by geographic location and size of the population aged >or=65 years and randomly allocated to receive CHAP or no intervention. In CHAP communities, residents aged >or=65 years were invited to attend cardiovascular risk assessment sessions held in pharmacies over 10 weeks in Fall, 2006. Sessions included blood pressure measurement and feedback to family physicians. Trained volunteers delivered the program with support from pharmacists, community nurses and local organisations.
The primary outcome measure is the relative change in the mean annual rate of hospital admission for acute myocardial infarction, congestive heart failure and stroke (composite end-point) among residents aged >or=65 years in intervention and control communities, using routinely collected, population-based administrative health data.
This paper highlights considerations in design, implementation and evaluation of a large-scale, community-wide cardiovascular health promotion initiative.