Dataset Information

Do case-only designs yield consistent results across design and different databases? A case study of hip fractures and benzodiazepines.

ABSTRACT:

Background

The case-crossover (CXO) and self-controlled case series (SCCS) designs are increasingly used in pharmacoepidemiology. In both, relative risk estimates are obtained within persons, implicitly controlling for time-fixed confounding variables.

Objectives

To examine the consistency of relative risk estimates of hip/femur fractures (HFF) associated with the use of benzodiazepines (BZD) across case-only designs in two databases (DBs), when a common protocol was applied.

Methods

CXO and SCCS studies were conducted in BIFAP (Spain) and CPRD (UK). Exposure to BZD was divided into non-use, current, recent and past use. For CXO, odds ratios (OR; 95%CI) of current use versus non-use/past were estimated using conditional logistic regression adjusted for co-medications (AOR). For the SCCS, conditional Poisson regression was used to estimate incidence rate ratios (IRR; 95%CI) of current use versus non/past-use, adjusted for age. To investigate possible event-exposure dependence the relative risk in the 30 days prior to first BZD exposure was also evaluated.

Results

In the CXO current use of BZD was associated with an increased risk of HFF in both DBs, AORBIFAP = 1.47 (1.29-1.67) and AORCPRD = 1.55 (1.41-1.70). In the SCCS, IRRs for current exposure was 0.79 (0.72-0.86) in BIFAP and 1.21 (1.13-1.30) in CPRD. However, when we considered separately the 30-day pre-exposure period, the IRR for current period was 1.43 (1.31-1.57) in BIFAP and 1.37 (1.27-1.47) in CPRD.

Conclusions

CXO designs yielded consistent results across DBs, while initial SCCS analyses did not. Accounting for event-exposure dependence, estimates derived from SCCS were more consistent across DBs and designs.

SUBMITTER: Requena G

PROVIDER: S-EPMC4949640 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature

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Publications

Do case-only designs yield consistent results across design and different databases? A case study of hip fractures and benzodiazepines.

Requena Gema G Logie John J Martin Elisa E Boudiaf Nada N González González Rocío R Huerta Consuelo C Alvarez Arturo A Webb David D Bate Andrew A García Rodríguez Luis A LA Reynolds Robert R Schlienger Raymond R Gardarsdottir Helga H de Groot Mark M Klungel Olaf H OH de Abajo Fancisco F Douglas Ian J IJ

Pharmacoepidemiology and drug safety 20150626

<h4>Background</h4>The case-crossover (CXO) and self-controlled case series (SCCS) designs are increasingly used in pharmacoepidemiology. In both, relative risk estimates are obtained within persons, implicitly controlling for time-fixed confounding variables.<h4>Objectives</h4>To examine the consistency of relative risk estimates of hip/femur fractures (HFF) associated with the use of benzodiazepines (BZD) across case-only designs in two databases (DBs), when a common protocol was applied.<h4>M ...[more]

PMID: 26112821

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Project description:IntroductionClinical trial designs based on the assumption of independent observations are well established. Clustered clinical trial designs, where all observational units belong to a cluster and outcomes within clusters are expected to be correlated, have also received considerable attention. However, many clinical trials involve partially clustered data, where only some observational units belong to a cluster. Examples of such trials occur in neonatology, where participants include infants from both singleton and multiple births, and ophthalmology, where one or two eyes per participant may need treatment. Partial clustering can also arise in trials of group-based treatments (e.g. group education or counselling sessions) or treatments administered individually by a discrete number of health care professionals (e.g. surgeons or physical therapists), when this is compared to an unclustered control arm. Trials involving partially clustered data have received limited attention in the literature and the current lack of standardised terminology may be hampering the development and dissemination of methods for designing and analysing these trials.Methods and examplesIn this article, we present an overarching definition of partially clustered trials, bringing together several existing trial designs including those for group-based treatments, clustering due to facilitator effects and the re-randomisation design. We define and describe four types of partially clustered trial designs, characterised by whether the clustering occurs pre-randomisation or post-randomisation and, in the case of pre-randomisation clustering, by the method of randomisation that is used for the clustered observations (individual randomisation, cluster randomisation or balanced randomisation within clusters). Real life examples are provided to highlight the occurrence of partially clustered trials across a variety of fields. To assess how partially clustered trials are currently reported, we review published reports of partially clustered trials.DiscussionOur findings demonstrate that the description of these trials is often incomplete and the terminology used to describe the trial designs is inconsistent, restricting the ability to identify these trials in the literature. By adopting the definitions and terminology presented in this article, the reporting of partially clustered trials can be substantially improved, and we present several recommendations for reporting these trial designs in practice. Greater awareness of partially clustered trials will facilitate more methodological research into their design and analysis, ultimately improving the quality of these trials.

Project description:BackgroundVarious nerve blocks with local anaesthetic agents have been used to reduce pain after hip fracture and subsequent surgery. This review was published originally in 1999 and was updated in 2001, 2002, 2009 and 2017.ObjectivesThis review focuses on the use of peripheral nerves blocks as preoperative analgesia, as postoperative analgesia or as a supplement to general anaesthesia for hip fracture surgery. We undertook the update to look for new studies and to update the methods to reflect Cochrane standards.Search methodsFor the updated review, we searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), MEDLINE (Ovid SP, 1966 to August week 1 2016), Embase (Ovid SP, 1988 to 2016 August week 1) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO, 1982 to August week 1 2016), as well as trial registers and reference lists of relevant articles.Selection criteriaWe included randomized controlled trials (RCTs) involving use of nerve blocks as part of the care provided for adults aged 16 years and older with hip fracture.Data collection and analysisTwo review authors independently assessed new trials for inclusion, determined trial quality using the Cochrane tool and extracted data. When appropriate, we pooled results of outcome measures. We rated the quality of evidence according to the GRADE Working Group approach.Main resultsWe included 31 trials (1760 participants; 897 randomized to peripheral nerve blocks and 863 to no regional blockade). Results of eight trials with 373 participants show that peripheral nerve blocks reduced pain on movement within 30 minutes of block placement (standardized mean difference (SMD) -1.41, 95% confidence interval (CI) -2.14 to -0.67; equivalent to -3.4 on a scale from 0 to 10; I2 = 90%; high quality of evidence). Effect size was proportionate to the concentration of local anaesthetic used (P < 0.00001). Based on seven trials with 676 participants, we did not find a difference in the risk of acute confusional state (risk ratio (RR) 0.69, 95% CI 0.38 to 1.27; I2 = 48%; very low quality of evidence). Three trials with 131 participants reported decreased risk for pneumonia (RR 0.41, 95% CI 0.19 to 0.89; I2 = 3%; number needed to treat for an additional beneficial outcome (NNTB) 7, 95% CI 5 to 72; moderate quality of evidence). We did not find a difference in risk of myocardial ischaemia or death within six months, but the number of participants included was well below the optimal information size for these two outcomes. Two trials with 155 participants reported that peripheral nerve blocks also reduced time to first mobilization after surgery (mean difference -11.25 hours, 95% CI -14.34 to -8.15 hours; I2 = 52%; moderate quality of evidence). One trial with 75 participants indicated that the cost of analgesic drugs was lower when they were given as a single shot block (SMD -3.48, 95% CI -4.23 to -2.74; moderate quality of evidence).Authors' conclusionsHigh-quality evidence shows that regional blockade reduces pain on movement within 30 minutes after block placement. Moderate-quality evidence shows reduced risk for pneumonia, decreased time to first mobilization and cost reduction of the analgesic regimen (single shot blocks).

Dataset Information

Do case-only designs yield consistent results across design and different databases? A case study of hip fractures and benzodiazepines.

Background

Objectives

Methods

Results

Conclusions

Publications

Do case-only designs yield consistent results across design and different databases? A case study of hip fractures and benzodiazepines.

Similar Datasets

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