Scientific
publications

PURPOSE: Chronic kidney disease (CKD) is a prevalent and important outcome and covariate in pharmacoepidemiology. The Health Improvement Network (THIN) in the UK represents a unique resource for population-based studies of CKD. We compiled a valid list of Read codes to identify subjects with moderate to advanced CKD. METHODS: A cross-sectional validation study was performed to identify codes that best define CKD Stages 3-5. All subjects with at least one non-zero measure of serum creatinine after 1 January 2002 were included. Estimated glomerular filtration rate (eGFR) was calculated according to the Schwartz formula for subjects aged < 18 years and the Modification of Diet in Renal Disease formula for subjects aged ≥ 18 years. CKD was defined as an eGFR <60 mL/minute/1.73 m² on at least two occasions, more than 90 days apart. RESULTS: The laboratory definition identified 230,426 subjects with CKD, for a period prevalence in 2008 of 4.56% (95%CI, 4.54-4.58). A list of 45 Read codes was compiled, which yielded a positive predictive value of 88.9% (95%CI, 88.7-89.1), sensitivity of 48.8%, negative predictive value of 86.5%, and specificity of 98.2%. Of the 11.1% of subjects with a code who did not meet the laboratory definition, 83.6% had at least one eGFR <60. The most commonly used code was for CKD Stage 3. CONCLUSIONS: The proposed list of codes can be used to accurately identify CKD when serum creatinine data are limited. The most sensitive approach for the detection of CKD is to use this list to supplement creatinine measures.

BACKGROUND: There is pressing need to diagnose lung cancer earlier in the United Kingdom (UK) and it is likely that research using computerised general practice records will help this process. Linkage of these records to area-level geo-demographic classifications may also facilitate case ascertainment for public health programmes, however, there have as yet been no extensive studies of data validity for such purposes. METHODS: To first address the need for validation, we assessed the completeness and representativeness of lung cancer data from The Health Improvement Network (THIN) national primary care database by comparing incidence and survival between 2000 and 2009 with the UK National Cancer Registry and the National Lung Cancer Audit Database. Secondly, we explored the potential of a geo-demographic social marketing tool to facilitate disease ascertainment by using Experian's Mosaic Public Sector ™ classification, to identify detailed profiles of the sectors of society where lung cancer incidence was highest. RESULTS: Overall incidence of lung cancer (41.4/100, 000 person-years, 95% confidence interval 40.6-42.1) and median survival (232 days) were similar to other national data; The incidence rate in THIN from 2003-2006 was found to be just over 93% of the national cancer registry rate. Incidence increased considerably with area-level deprivation measured by the Townsend Index and was highest in the North-West of England (65.1/100, 000 person-years). Wider variations in incidence were however identified using Mosaic classifications with the highest incidence in Mosaic Public Sector ™types 'Cared-for pensioners, ' 'Old people in flats' and 'Dignified dependency' (191.7, 174.2 and 117.1 per 100, 000 person-years respectively). CONCLUSIONS: Routine electronic data in THIN are a valid source of lung cancer information. Mosaic ™ identified greater incidence differentials than standard area-level measures and as such could be used as a tool for public health programmes to ascertain future cases more effectively.

OBJECTIVE: Adhesive capsulitis (AC) is a painful shoulder disorder resulting in restrictions of daily activities. Given the recent increase in risk factors for AC, such as diabetes mellitus, research is needed to examine if the incidence of AC has also increased. Therefore, the purpose of this study was to describe the secular trend of AC. METHODS: Subjects were from The Health Improvement Network, an electronic medical record database of general practices across the UK from 1995-2008. General practitioners diagnosed AC. We included subjects ages 40-79 years and defined an incident case as the first diagnosis of AC following at least 1 year of enrollment in the database. We examined the potential independent effects of age, calendar time, and birth cohort using an age-period-cohort model. To approximate effect estimates, we applied proportional hazards models and separately adjusted for diabetes mellitus. RESULTS: Of 2,188,958 subjects (50.0% women), the incidence of AC was 2.36 and 3.38 per 1,000 person-years for men and women, respectively. Age-period-cohort model graphs suggested a secular trend due to a birth cohort, but not calendar effect. For each 10-year increment in birth cohort, the incidence rate increased by 8% in women (hazard ratio 1.08, 95% confidence interval 1.05-1.13). There was no increase in AC incidence for men. Adjusting for diabetes mellitus did not change these associations materially. CONCLUSION: We found women born more recently are at a higher risk of developing AC compared with women born earlier. Future research is needed to identify risk factors that may be responsible for this increase.

OBJECTIVE: To assess trends in long-term (i.e. ≥3 months) oral glucocorticoid (GC) prescriptions over the past 20 years. METHODS: Data of UK adult patients registered between January 1989 and December 2008 with general practices contributing to The Health Improvement Network (THIN) database were obtained. The annual prevalence of long-term oral GC prescriptions was assessed in the whole population and specifically in people with RA, PMR/GCA, asthma, chronic obstructive pulmonary disease (COPD), Crohn's disease and ulcerative colitis (UC). Trends over the 20-year period were estimated using sex- and age-adjusted Poisson regression models. RESULTS: During the 26 035 154 person-years of follow-up, an average of 0.75% (95% CI 0.74, 0.75) of the study population was prescribed long-term oral GC therapy at any time point. This rose from 0.59% (0.52, 0.67) in 1989 to 0.79% (0.78, 0.80) in 2008. Long-term prescriptions significantly increased in patients with RA [from 10.3% (8.7, 11.9) to 13.6% (12.9, 14.2)] and PMR/GCA [from 57.6% (53.3, 62.0) to 66.5% (65.2, 67.7)], decreased in patients with asthma, COPD and Crohn's disease and remained stable in patients with UC. However, when only incident cases were considered, we found a decreased use of GCs in patients with RA and UC [odds ratio 0.97 (95% CI 0.96, 0.97) and 0.94 (95% CI 0.93, 0.96) per increasing year, respectively]. CONCLUSION: Over the past 20 years, long-term oral GC prescriptions have increased by 34%. Patients newly diagnosed with RA, Crohn's disease or UC are, however, less likely to receive long-term GC prescriptions than patients with a long past medical history of the disease, suggesting changes in physicians' practice.

PURPOSE: Very little is known about oral glucocorticoids (GCs) prescriptions in general population. METHODS: Data of UK adult patients registered between January 1989 and December 2008 with general practices contributing to The Health Improvement Network (THIN) database were analyzed. We identified all patients aged 18 years and older who received at least one oral GCs prescription. Short-term treatments (i.e., <3 months) were differentiated from long term (i.e., ≥3 months) ones. Demographical data of patients being prescribed such treatments and reason for prescriptions over the 20 years were described. The annual prevalence of GCs prescriptions was assessed. RESULTS: The study population consisted of 4,518,753 adult patients (26,035,154 person-years of follow-up). Overall, 810,009 oral GCs treatments (220,195,154 person-years of follow-up) were prescribed in 384,897 patients. Over the 20 years, the mean prevalence of oral GCs prescriptions was 0.85% [0.84-0.85], increasing from 0.65% [0.57-0.74] in 1989 to 0.91% [0.90-0.93] in 2008. Short-term therapies (median duration of prescription: 9 days [6-10], median cumulative prednisone equivalent (PE) dosage: 210 mg [150-420]) represented 79.3% of treatments and 11.9% of prevalence whereas it was the opposite for long term prescriptions (median duration of prescription: 215 days [126-490], median cumulative PE dosage: 2000 mg [950-4310]). Women were more prescribed GCs. Median age at first GCs prescription was 56.1 years [39.4-70.4] and 67.4 years [54.0-76.8] for short-term and long-term therapies, respectively. Reasons for prescription were mainly pulmonary diseases. CONCLUSION: About 1% of the UK general population receives GCs therapy in any point of time. This prevalence has constantly increased over the last 20 years.