J Maskell

Explaining the rise in antidepressant prescribing: a descriptive study using the general practice research database

Objective To explore the reasons behind the recent increase in antidepressant prescribing in the United Kingdom. Design Detailed retrospective analysis of data on general practitioner consultations and antidepressant prescribing. Data source Data were obtained from the general practice research database, which contains linked anonymised records of over 3 million patients registered in the UK. Data were extracted for all new incident cases of depression between 1993 and 2005. Review methods Detailed analysis of general practitioner consultations and antidepressant prescribing was restricted to 170 practices that were contributing data for the full duration of the study. Results In total, 189 851 people within the general practice research database experienced their first episode of depression between 1993 and 2005, of whom 150 825 (79.4%) received a prescription for antidepressants in the first year of diagnosis. This proportion remained stable across all the years examined. The incidence of new cases of depression rose in young women but fell slightly in other groups such that overall incidence increased then declined slightly (men: 7.83 cases per 1000 patient years in 1993 to 5.97 in 2005, women: 15.83 cases per 1000 patient years in 1993 to 10.06 in 2005). Antidepressant prescribing nearly doubled during the study period—the average number of prescriptions issued per patient increased from 2.8 in 1993 to 5.6 in 2004. The majority of antidepressant prescriptions were given as long term treatment or as intermittent treatment to patients with multiple episodes of depression. Conclusions The rise in antidepressant prescribing is mainly explained by small changes in the proportion of patients receiving long term treatment. Previous clinical guidelines have focused on antidepressant initiation and appropriate targeting of antidepressants. To address the costly rise in antidepressant prescribing, future research and guidance needs to concentrate on appropriate long term prescribing for depression and regular review of medication.

Future projections of total hip and knee arthroplasty in the UK: results from the UK Clinical Practice Research Datalink

OBJECTIVE To estimate the future rate of primary total hip (THR) or knee (TKR) replacement in the UK to 2035 allowing for changes in population demographics and obesity. DESIGN Using age/gender/body mass index (BMI)-specific incidence rates from a population-based cohort study of 50,000 THR and 45,609 TKR patients from the UK Clinical Practice Research Datalink (CPRD) between 1991 and 2010, we projected future numbers of THR and TKR using two models: a static, estimated rate from 2010 applied to population growth forecasts to 2035, and a log-linear rate extrapolation over the same period. Both scenarios used population forecast data from the UK Office for National Statistics (ONS). RESULTS Assuming rates of THR and TKR for 2010, and given projected population changes in age, gender and BMI, the number of THRs and TKRs performed in the UK in 2035 is estimated to be, respectively: 95,877 and 118,666. By comparison, an exponential extrapolation of historical rates using a log-linear model produces much higher estimates of THR and TKR counts in 2035 at 439,097 and 1,219,362 respectively. Projected counts were higher for women than men. Assuming a changing (rather than fixed) future BMI distribution increases TKRs by 2035 but not THRs. CONCLUSIONS Using historical rates and population forecasts we have projected the number of THR/TKR operations in the UK up to 2035. This study will inform policymakers requiring estimates of future demand for surgery. Incorporating future forecasts for BMI into projections of joint replacement may be more relevant for TKR rather than THR.

Introduction of Complementary Foods and the Relationship to Food Allergy

OBJECTIVES: To address questions regarding breastfeeding, complementary feeding, allergy development, and current infant-feeding recommendations. METHODS: This was a nested, case-control within a cohort study in which mothers of 41 infants diagnosed with food allergy by the age of 2 years (according to double-blind, placebo-controlled food challenge) and their 82 age-matched controls kept prospective food diaries of how their infants were fed in the first year of life. RESULTS: Infants who were diagnosed with food allergy by the time they were 2 years of age were introduced to solids earlier (≤16 weeks of age) and were less likely to be receiving breast milk when cow’s milk protein was first introduced into their diet. CONCLUSIONS: This study supports the current American Academy of Pediatrics’ allergy prevention recommendations and the European Society of Pediatric Gastroenterology, Hepatology and Nutrition recommendations on complementary feeding to not introduce solids before 4 to 6 months of age. It also supports the American Academy of Pediatrics’ breastfeeding recommendations that breastfeeding should continue while solids are introduced into the diet and that breastfeeding should continue for 1 year, or longer, as mutually desired by mother and infant.

Mortality in Wegener’s granulomatosis: a bimodal pattern

OBJECTIVE To characterize the long-term mortality in patients with WG compared with matched population-based controls. METHODS We used data from the General Practice Research Database, which contains the computerized records of 6.25 million patients and is representative of the population of the UK. We identified all subjects with a new diagnosis of WG in the period 1989-2004, and for each case, compared mortality with 10 controls matched for age, gender and practice. RESULTS We identified 255 patients with a new diagnosis of WG (mean age 58.1 years, range 9-90 years, 47% females) and 2546 controls (mean age 58.1 years, range 9-89 years, 47% females). Mean follow-up was 6.4 years. The mortality for patients with WG was significantly increased during the first year after diagnosis [HR 9.0 (95% CI 5.8, 13.9)], especially for those ≤ 65 years of age [HR 19.9 (95% CI 8.8, 44.9)]. The excess mortality was less marked after the first year: 1-5 years [HR 1.68 (95% CI 1.08, 2.60)], 5-10 years [HR 2.41 (95% CI 1.43, 4.07)], but started to increase by 10-15 years [HR 4.4 (95% CI 2.0, 9.8)]. The Kaplan-Meier survival curve showed an increase in mortality after 8 years. CONCLUSIONS Despite current therapy, patients with WG have a 9-fold increased risk of death in the first year of disease, attributed to infection, active vasculitis and renal failure. Between 1 and 8 years the risk is at its lowest, although higher than the control population. There is an increased mortality from 8 years onwards that remains unexplained.

A population-based survival analysis describing the association of body mass index on time to revision for total hip and knee replacements: results from the UK general practice research database.

Objectives Against a backdrop of rising levels of obesity, we describe and estimate associations of body mass index (BMI), age and gender with time to revision for participants undergoing primary total hip (THR) or knee (TKR) replacement in the UK. Design Population-based cohort study. Setting Routinely collected primary care data from a representative sample of general practices, including linked data on all secondary care events. Participants Population-based cohort study of 63 162 patients with THR and 54 276 with TKR in the UK General Practice Research Database between 1988 and 2011. Primary and secondary outcomes Risk of THR and TKR revision associated with BMI, age and gender, after adjusting for the competing risk of death. Results The 5-year cumulative incidence rate for THR was 2.2% for men and 1.8% for women (TKR 2.3% for men, 1.6% for women). The adjusted overall subhazard ratio (SHR) for patients with THR undergoing subsequent hip revision surgery, with a competing risk of death, were estimated at 1.020 (95% CI 1.009 to 1.032) per additional unit (kg/m2) of BMI, 1.23 (95% CI 1.10 to 1.38) for men compared with women and 0.970 (95% CI 0.967 to 0.973) per additional year of age. For patients with TKR, the equivalent estimates were 1.015 (95% CI 1.002 to 1.028) for BMI; 1.51 (95% CI 1.32 to 1.73) for gender and 0.957 (95% CI 0.951 to 0.962) for age. Morbidly obese patients with THR had a 65.5% increase (95% CI 15.4% to 137.3%, p=0.006) in the subhazard of revision versus the normal BMI group (18.5–25). The effect for TKR was smaller (a 43.9% increase) and weaker (95% CI 2.6% to 103.9%, p=0.040). Conclusions BMI is estimated to have a small but statistically significant association with the risk of hip and knee revision, but absolute numbers are small. Further studies are needed in order to distinguish between effects for specific revision surgery indications.

Which Patients with Giant Cell Arteritis Will Develop Cardiovascular or Cerebrovascular Disease? A Clinical Practice Research Datalink Study

Objective. To evaluate the risk of cerebrovascular disease and cardiovascular disease (CVD) in patients with giant cell arteritis (GCA), and to identify predictors. Methods. The UK Clinical Practice Research Datalink 1991–2010 was used for a parallel cohort study of 5827 patients with GCA and 37,090 age-, sex-, and location-matched controls. A multivariable competing risk model (non-cerebrovascular/CV-related death as the competing risk) determined the relative risk [subhazard ratio (SHR)] between patients with GCA compared with background controls for cerebrovascular disease, CVD, or either. Each cohort (GCA and controls) was then analyzed individually using the same multivariable model, with age and sex now present, to identify predictors of CVD or cerebrovascular disease. Results. Patients with GCA, compared with controls, had an increased risk SHR (95% CI) of cerebrovascular disease (1.45, 1.31–1.60), CVD (1.49, 1.37–1.62), or either (1.47, 1.37–1.57). In the GCA cohort, predictors of “cerebrovascular disease or CVD” included increasing age, > 80 years versus < 65 years (1.98, 1.62–2.42), male sex (1.20, 1.05–1.38), and socioeconomic status, most deprived quintile versus least deprived (1.34, 1.01–1.78). These predictors were also present within the non-GCA cohort. Conclusion. Patients with GCA are more likely to develop cerebrovascular disease or CVD than age-, sex-, and location-matched controls. In common with the non-GCA cohort, patients who are older, male, and from the most deprived compared with least deprived areas have a higher risk of cerebrovascular disease or CVD. Further work is needed to understand how this risk may be mediated by specific behavioral, social, and economic factors.

Prospective food diaries demonstrate breastfeeding characteristics in a UK birth cohort.

Breastfeeding duration and exclusive breastfeeding rates are universally below those recommended by World Health Organization. Due to limitations and challenges associated with researching breastfeeding characteristics, the times when exclusivity is likely to be lost and when women are most likely to discontinue breastfeeding have not yet been identified. Prospective food diaries allow reliable description of the dynamics of breastfeeding to be made to help identify these key time periods. Food diaries detailing intake from birth until the cessation of breastfeeding were analysed for 718 infants recruited into a national arm of an international multicentre birth cohort study (EuroPrevall). Analyses included linear regression analysis and Kaplan-Meier time course analysis. Breastfeeding and exclusive breastfeeding cessation rates for younger mothers (<25 years) are high in the first few weeks after delivery but slow markedly in the period 10-12 weeks after delivery. Cessation rates are consistent from 0 to 26 weeks in older mothers. This difference in feeding patterns led to significant differences between the two different age groups at 26 weeks for breastfeeding (P = 0.006) and exclusive breastfeeding at 8 weeks (P = 0.009). Forty-nine per cent of younger mothers (<25 years) stopped breastfeeding before their infant was 3 weeks old. To increase breastfeeding duration, further work is required to investigate the attitudes and perceptions associated with such high breastfeeding cessation rates in younger mothers during these very early post-natal weeks.