Comparability of the age and sex distribution of the UK Clinical Practice Research Datalink and the total Dutch population

Patterns of rates of mortality in the Clinical Practice Research Datalink

The Clinical Practice Research Datalink (CPRD) is a widely used data resource, representative in demographic profile, with accurate death recordings but it is unclear if mortality rates within CPRD GOLD are similar to rates in the general population. Rates may additionally be affected by selection bias caused by the requirement that a cohort have a minimum lookback window, i.e. observation time prior to start of at-risk follow-up. Standardised Mortality Ratios (SMRs) were calculated incorporating published population reference rates from the Office for National Statistics (ONS), using Poisson regression with rates in CPRD GOLD contrasted to ONS rates, stratified by age, calendar year and sex. An overall SMR was estimated along with SMRs presented for cohorts with different lookback windows (1, 2, 5, 10 years). SMRs were stratified by calendar year, length of follow-up and age group. Mortality rates in a random sample of 1 million CPRD GOLD patients were slightly lower than the national population [SMR = 0.980 95% confidence interval (CI) (0.973, 0.987)]. Cohorts with observational lookback had SMRs below one [1 year of lookback; SMR = 0.905 (0.898, 0.912), 2 years; SMR = 0.881 (0.874, 0.888), 5 years; SMR = 0.849 (0.841, 0.857), 10 years; SMR = 0.837 (0.827, 0.847)]. Mortality rates in the first two years after patient entry into CPRD were higher than the general population, while SMRs dropped below one thereafter. Mortality rates in CPRD, using simple entry requirements, are similar to rates seen in the English population. The requirement of at least a single year of lookback results in lower mortality rates compared to national estimates.

Under-recognition of heart failure in patients with atrial fibrillation and the impact of gender: a UK population-based cohort study

BACKGROUND

Patients with atrial fibrillation (AF) complicated by heart failure (HF) have a poor prognosis. We investigated whether long term loop-diuretic therapy in patients with AF and no known diagnosis of HF, as a potential surrogate marker of undiagnosed HF, is also associated with worse outcomes.

METHODS

Adults with incident AF were identified from UK primary and secondary care records between 2004 and 2016. Repeat prescriptions for loop diuretics, without a diagnosis of HF or documented non-cardiac indication, were classified as 'isolated' loop diuretic use.

RESULTS

Amongst 124,256 people with incident AF (median 76 years, 47% women), 22,001 (17.7%) had a diagnosis of HF, and 22,325 (18.0%) had isolated loop diuretic use. During 2.9 (LQ-UQ 1-6) years' follow-up, 12,182 patients were diagnosed with HF (incidence rate 3.2 [95% CI 3.1-3.3]/100 person-years). Of these, 3999 (32.8%) had prior isolated loop diuretic use, including 31% of patients diagnosed with HF following an emergency hospitalisation. The median time from AF to HF diagnosis was 3.6 (1.2-7.7) years in men versus 5.1 (1.8-9.9) years in women (p = 0.0001). In adjusted models, patients with isolated loop diuretic use had higher mortality (HR 1.42 [95% CI 1.37-1.47], p < 0.0005) and risk of HF hospitalisation (HR 1.60 [95% CI 1.42-1.80], p < 0.0005) than patients with no HF or loop diuretic use, and comparably poor survival to patients with diagnosed HF.

CONCLUSIONS

Loop diuretics are commonly prescribed to patients with AF and may indicate increased cardiovascular risk. Targeted evaluation of these patients may allow earlier HF diagnosis, timely intervention, and better outcomes, particularly amongst women with AF, in whom HF appears to be under-recognised and diagnosed later than in men.

The risk of community-acquired pneumonia in children using gastric acid suppressants

BACKGROUND

With the increased use of acid suppressants, significant potential complications such as community-acquired pneumonia (CAP) are becoming more apparent. Paradoxically, in spite of an increased focus on potential complications, there is an increased use of acid suppressants in children and a lack of data specifically targeting the association between acid suppressants and CAP. Our main objective was to evaluate the risk of CAP in children using acid suppressants (proton pump inhibitors (PPIs) and/or histamine-2 receptor antagonists (H2RAs)).

METHODS

We performed a cohort study using data from the UK Clinical Practice Research Datalink. All patients aged 1 month to 18 years with a prescription of acid suppressants were included and matched to up to four unexposed children. Time-varying Cox proportional hazards models were used to estimate the risk of CAP. The cohort consisted of 84 868 exposed and 325 329 unexposed children.

RESULTS

Current use of PPIs and H2RAs was associated with an increased risk of CAP (adjusted hazard ratio 2.05 (95% CI 1.90-2.22) and 1.80 (95% CI 1.67-1.94), respectively). The risk was even greater in patients with respiratory disease. Long-term use (≥211 days) of PPIs and H2RAs led to a significantly greater risk of CAP compared with short-term use (<31 days). After cessation of therapy, the risk remained increased for the following 7 months.

CONCLUSION

The use of acid suppressants in children was associated with a doubled risk of CAP. This risk increased with chronic use and respiratory disease, and remained increased after discontinuation of therapy.

Validated methods to identify patients with asthma-COPD overlap in healthcare databases: a systematic review protocol

INTRODUCTION

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) is characterised by patients presenting symptoms of both asthma and COPD. Many efforts have been made to validate different methods of identifying asthma-COPD overlap cases based on symptoms, spirometry and medical history in epidemiological studies using healthcare databases. There are various coding algorithm strategies that can be used and selection depends on targeted validation. The primary objectives of this systematic review are to identify validated methods (or algorithms) that identify patients with ACO from healthcare databases and summarise the reported validity measures of these methods.

METHODS

MEDLINE, EMBASE databases and the Web of Science will be systematically searched by using appropriate search strategies that are able to identify studies containing validated codes and algorithms for the diagnosis of ACO in healthcare databases published, in English, before October 2018. For each selected study, we require the presence of at least one test measure (eg, sensitivity, specificity etc). We will also include studies, in which the validated algorithm is compared with an external reference standard such as questionnaires completed by patients or physicians, medical charts review, manual review or an independent second database. For all selected studies, a uniform table will be created to summarise the following vital information: name of author, publication year, country, data source, population, clinical outcome, algorithms, reference standard method of validation and characteristics of the test measure used to determine validity.

PROSPERO REGISTRATION NUMBER

CRD42018087472.

Impact of the definition of osteoarthritis and of the timing of its onset on the association between type 2 diabetes mellitus and osteoarthritis: Clinical Practice Research Datalink

AIMS

In a previous case-control study in a large primary care database, the Clinical Practice Research Datalink (CPRD), type 2 diabetes mellitus (T2DM) was associated with a decreased rate of total joint replacement (TJR). As this was in contrast to the hypothesis, selection bias due to the used definition of osteoarthritis (OA) or misclassification of the onset of OA were raised as possible explanations. We therefore aimed to explore the effect of the definition of OA, and hypothesized timing of its onset on the association between T2DM and OA.

METHODS

All patients using a non-insulin anti-hyperglycaemic drug (NIAD) between 1989 and 2012 in the CPRD were included and matched to unexposed patients. Cox proportional hazard models were fitted estimating the risk of TJR or OA in T2DM patients compared to patients without T2DM. These analyses were repeated in sensitivity scenarios and joint-specific analyses. To assess whether misclassification of onset of OA may affect the association, analyses were repeated with addition of a latency period of up to 10 years after start of follow-up.

RESULTS

The use of TJR as a proxy for OA (hazard ratio (HR) = 0.74; 95% Confidence Interval (CI) = 0.70-0.78) resulted in a HR that was approximately 0.2 lower than when OA diagnostic codes were used (HR = 0.93; 95% CI = 0.90-0.95). The joint-specific subgroup analyses, sensitivity scenarios, and latency analyses showed similar results.

CONCLUSION

When examining the association between T2DM and OA, the use of TJR as a proxy for OA resulted in a 20% lower estimate than the OA diagnosis.

Use of Topical Tacrolimus and Topical Pimecrolimus in Four European Countries: A Multicentre Database Cohort Study

Background

Despite the concerns about a potential increased risk of skin cancer and lymphoma with the use of topical tacrolimus and pimecrolimus, no population-based studies have given an overview of the use of these drugs in Europe.

Objective

To assess the use of topical tacrolimus and pimecrolimus in children and adults in Europe.

Methods

Multicentre database cohort study comprising data from the Netherlands, Denmark, Sweden and the UK. We analysed users of topical tacrolimus and pimecrolimus starting from the date of first availability (between 2002 and 2003) or start establishment of the prescription database in Sweden (2006) through 2011. Use was assessed separately for children (≤ 18 years) and adults.

Results

32,052 children and 104,902 adults were treated with topical tacrolimus, and 32,125 children and 58,280 adults were treated with topical pimecrolimus. The number of users increased rapidly after first availability, especially for topical tacrolimus. Topical tacrolimus was more frequently used in all countries except Denmark. For both drugs, there was a decrease in users after 2004 in the Netherlands and Denmark and after 2005 in the UK, especially among children. This decrease was largest in Denmark. The decrease in the number of users was temporary for topical tacrolimus, while use remained relatively low for topical pimecrolimus.

Conclusions

The number of topical tacrolimus and pimecrolimus users increased rapidly after regulatory approval. A transient reduction in topical tacrolimus use and a persistent reduction in topical pimecrolimus use was seen after 2004 in the Netherlands and Denmark and after 2005 in the UK.