Changes in medication associated with epilepsy-related hospitalisation: a case-crossover study

Association between opioid analgesic plus benzodiazepine use and death: A case-crossover study

OBJECTIVE

We aimed to investigate whether concomitant use of benzodiazepines and opioids is associated with an increased risk of death in a population-based case-crossover setting.

METHODS

We conducted a case-crossover study using the National Sample Cohort database. We introduced a 30-day hazard period before the onset of death and three consecutive previous 30-day control periods with a 30-day washout period. The use of opioids and/or benzodiazepines during the hazard period was compared with that in the three control periods. We performed the conditional logistic regression analysis to estimate the adjusted odds ratios (aORs) and their 95% confidence intervals (CIs).

RESULTS

A total of 13,161 individuals who previously used benzodiazepines or opioids and died were included in the study. The risk of death was higher in patients with concomitant use of benzodiazepines and opioids (aOR, 1.86; 95% CI, 1.71-2.02) than in those who used either benzodiazepines or opioids only. In the subgroup analysis among concomitant users, the mortality risks were highest in patients aged less than 20 years (aOR, 3.85; 95% CI, 1.65-8.99), male patients (aOR, 2.20; 95% CI, 1.93-2.51), and patients with renal disease (aOR, 2.42; 95% CI, 1.57-3.74).

CONCLUSION

In this study, concomitant use of benzodiazepines and opioids was associated with a higher risk of death compared with use of a single drug. The risks and benefits of co-prescribing of benzodiazepines and opioids must be weighed carefully.

Anti-epileptic drug changes and quality of life in the community

OBJECTIVE

Changes in anti-epileptic drug (AED) regimens may indicate unsatisfactory treatment results such as insufficient seizure control or adverse effects. This inference underlies epilepsy management and research, yet current studies often do not account for AED changes. We assessed AED change patterns and their association with quality of life (QoL), as main outcome measure, in a community-based setting.

METHODS

We assessed a cohort of 248 people with epilepsy identified from community pharmacy records from whom we retrieved AED dispensing history. We assessed all changes in AED use during the 2 years prior to the index date and current QoL using the validated Dutch QOLIE-31 questionnaire.

RESULTS

Thirty-one per cent had at least one AED change during the study period, either in drug type or dose. People who changed showed significantly lower QoL (QOLIE score 73 vs 79), especially those who intensified their treatment. Each additional change was associated with a further reduction of 4.9 points in QoL score.

CONCLUSIONS

AED changes are common practice, even in people with long-standing epilepsy. Frequent changes, as objective measure of epilepsy severity, are associated with a progressively lower QoL. Changes, even in dose, should be monitored in daily clinical practice and used as a red flag that may require adjustments in epilepsy management. This may include earlier referral to a specialized centre for a more thorough evaluation or counselling. AED changes can also be used as an outcome marker in epilepsy research as a proxy of QoL for better translation of drug-efficacy results to general practice.

Medication information seeking behavior of patients who use multiple medicines: how does it affect adherence?

OBJECTIVE

This article explores medication information seeking behavior (MISB). We aimed to develop a scale for measuring MISB and use it to explore the relationships between MISB, adherence and factors, which drive information seeking.

METHODS

Patients (N=910) using multiple medicines completed questionnaires. Exploratory and confirmatory factor analyses were performed. Correlations and multivariate analyses were used to investigate the relationships between variables.

RESULTS

Respondents sought medication information mainly from health professionals and written medicines information. The medication information seeking behavior scale (MISB) had acceptable reliability and validity. Information seeking was most intense among respondents who had recent changes in their medicine regimen and worries about their medicines. Those who sought medication information from autonomous sources were more likely to be non-adherent than those who never did (OR=2.00 [1.48, 2.70]). Seeking information from health professionals had no influence on adherence.

CONCLUSION

Health practitioners should carefully attend to patients' questions about medicines information. When patients mention that they are worried about their medicines and have sought medication information from television, magazines, brochures or family and friends, this could be a sign that they tend towards non-adherent behavior.

PRACTICE IMPLICATIONS

The MISB scale could be used to learn more about patients' use of medication information.

Newly initiated opioid treatment and the risk of fall-related injuries. A nationwide, register-based, case-crossover study in Sweden

BACKGROUND

There is growing epidemiological evidence that opioids may increase the risk of unintentional injuries and it is plausible that the time of initiation is most critical in that respect. Studies on fall-related injuries remain few, limited and mostly focused on specific groups of elderly patients.

OBJECTIVE

The objective of this study was to assess the short-term effects of newly prescribed opioids on the risk of fall-related injuries in the general adult population.

METHODS

A case-crossover design was applied on national register data linking, at the individual level, fall-injury information involving adults aged 18 years and above identified in the Swedish National Inpatient Register (during the period 1 May 2006 to 31 December 2009) and dispensed drugs from the Swedish Prescribed Drug Register (n=167,257 cases with a first fall-related injury). All types of opioid substances were considered, classified according to the Anatomical Therapeutic Chemical (ATC) classification system. We investigated newly dispensed opioids 28 days preceding the injury, compared with an earlier, and equally long, control period following a 3-month washout period. Conditional logistic regression was used to estimate odds ratio (OR) and 95% confidence interval (CI). The analyses were also conducted stratified by age group, by type of fall and for each period of 1 week during the 28-day period.

RESULTS

From among the fall-injured patients, 7,450 patients (4.5%) had a new opioid dispensation within 28 days prior to the injury, of which the most frequent types were tramadol (2.0%) and codeine (1.1%). Consistently increased risks of fall-related injuries associated with a new prescription of any opioid were found and they were most pronounced among young adults, 18-29 years of age (OR, 7.17; 95% CI 5.04-10.2). The closer the dispensation date to the injury, the higher the odds: an OR of 5.14 (95% CI 4.76-5.55) during the first week of opioid treatment and 1.23 (95% CI 1.10-1.38) for the fourth week. Of the documented falls, the risk was most pronounced for falls from 'another, high level' (OR, 5.33; 95% CI 3.99-7.10).

CONCLUSIONS

Newly prescribed opioids may trigger injurious falls. The effect lowers over time and is less pronounced with increasing age. The risk is also higher for fall from height.

Medication changes prior to hospitalization for obstructive lung disease: a case-crossover study

BACKGROUND

Hospitalizations have always been seen as a solid outcome parameter in pharmacoepidemiology. However, the period leading to hospitalization and prehospital management of the patient are equally important.

OBJECTIVE

To evaluate medication changes in the period prior to hospitalization for obstructive lung disease and to quantify the association between medication use and the risk of hospitalization.

METHODS

We conducted a case-crossover study using the PHARMO record linkage system, which contains drug dispensing data from community pharmacies and hospital admission data. Patients included in the study were adults hospitalized for obstructive lung disease between 2005 and 2007. The index date of the case period was the date of hospitalization, and control moments were set at 3, 6, 9, and 12 months before admission. For each patient, all prescriptions prior to the date of hospitalization were identified. Medication use was ascertained in a 90-day time window prior to each case or control moment.

RESULTS

We identified 1481 patients who were hospitalized for obstructive lung disease. It appeared that respiratory medication use increased in the 90 days prior to hospitalization. Hospitalization was associated with the use of 3 or more respiratory drugs (OR 2.2; 95% CI 1.8 to 2.8), systemic glucocorticoids (OR 4.5; 95% CI 3.8 to 5.4), and antibiotics (OR 3.1; 95% CI 2.7 to 3.6).

CONCLUSIONS

The use of systemic glucocorticoids, antibiotics, and other respiratory drugs increased prior to hospitalization for obstructive lung disease. These results could be indicative of the development and/or treatment of an exacerbation. There is a need for markers to detect exacerbations in an early phase in order to start treatment as early as possible and possibly prevent hospitalizations for obstructive lung disease.

Drug treatment-related factors of inadequate seizure control

To optimize seizure control it is important to identify modifiable factors. We conducted a case-control study to explore to what extent drug treatment-related factors are associated with seizures. Eighty-six patients with epilepsy were evaluated: 45 cases (recently experienced a seizure) and 41 controls (seizure-free for at least 2 months). There was a significant association between low AED serum concentration and seizures (odds ratio (OR)=8.9, 95% confidence interval (CI)=1.7-47.8), compliance was not associated with seizures (OR=0.9, 95% CI=0.2-4.0), and changes in medication (mainly non-AEDs) were more frequently observed in the case group than in the control group (OR=4.1, 95% CI=0.9-18.3). These findings indicate that patients with low AED serum levels have a nine times higher risk of seizures compared with patients with therapeutic AED levels and that changes in medication regimens in patients with epilepsy should be made with care.

The case-crossover study design in pharmacoepidemiology

In the study of the association of transient drug exposures with acute outcomes, the case-crossover design is an efficient alternative to the case-control approach. This design based exclusively on the case series uses within-subject comparisons of drug exposures over time to estimate the rate ratio of the outcome associated with the drug under study. This design inherently removes the biasing effects of unmeasured, time-invariant confounding factors from the estimated rate ratio, but is sensitive to several assumptions. We illustrated the case-crossover design and explored its sensitivity using data from 4028 cases of gastrointestinal bleeding from the General Practice Research Database in assessing the effects of the drug warfarin. We compared the use of different time window lengths to assess exposure and considered the use of a case-time-control design to account for exposure time trends. The case-crossover approach found no excess risk of bleeding with warfarin exposure [rate ratio 0.98; 95% confidence interval (CI): 0.74-1.28] using a 1-month time window. When we restricted the analysis to subjects with truly transient drug exposure, defined by 1 to 3 prescriptions in the previous year, the rate ratio was 2.59 (95% CI: 1.42-4.74). To consider the longer 1-year exposure time window, the case-time-control approach was used and resulted in a rate ratio of 1.72 (95% CI: 1.08-2.43). In conclusion, the case-crossover design is potentially a powerful approach to assess the risk of drugs. This design is, however, highly sensitive to assumptions about intermittency of drug use and the length of the exposure time window, as demonstrated with the example of bleeding associated with warfarin use.