CYP2D6-Inhibiting Drugs and the Increased Risk of Fall-Related Injuries Due to Newly Initiated Opioid Treatment - A Swedish, Register-Based Case-Crossover Study

Evaluating the use of methods to mitigate bias from non-transient medications in the case-crossover design: A systematic review

PURPOSE

The case-crossover design is a self-controlled study design used to compare exposure immediately preceding an event occurrence with exposure in earlier control periods. The design is most suitable for transient exposures in order to avoid biases that can be problematic when using the case-crossover design for non-transient (i.e., chronic) exposures. Our goal was to conduct a systematic review of case-crossover studies and its variants (case-time-control and case-case-time-control) in order to compare design and analysis choices by medication type.

METHODS

We conducted a systematic search to identify recent case-crossover, case-time-control, and case-case-time-control studies focused on medication exposures. Articles indexed in MEDLINE and EMBASE using these study designs that were published between January 2015 and December 2021 in the English language were identified. Reviews, methodological studies, commentaries, articles without medications as the exposure of interest, and articles with no available full text were excluded. Study characteristics including study design, outcome, risk window, control window, reporting of discordant pairs, and inclusion of sensitivity analyses were summarized overall and by medication type. We further evaluated the implementation of recommended methods to account for biases introduced by non-transient exposures among articles that used the case-crossover design on a non-transient exposure.

RESULTS

Of the 2036 articles initially identified, 114 articles were included. The case-crossover was the most common study design (88%), followed by the case-time-control (17%), and case-case-time-control (3%). Fifty-three percent of the articles included only transient medications, 35% included only non-transient medications, and 12% included both. Across years, the proportion of case-crossover articles evaluating a non-transient medication ranged from 30% in 2018 to 69% in 2017. We found that 41% of the articles that evaluated a non-transient medication did not apply any of the recommended methods to account for biases and more than half of which were conducted by authors with no previous publication history of case-crossover studies.

CONCLUSION

Using the case-crossover design to evaluate a non-transient medication remains common in pharmacoepidemiology. Researchers should apply appropriate design and analysis choices when opting to use a case-crossover design with non-transient medication exposures.

Opioids and Falls Risk in Older Adults: A Narrative Review

Pain treatment is important in older adults but may result in adverse events such as falls. Opioids are effective for nociceptive pain but the evidence for neuropathic pain is weak. Nevertheless, both pain and opioids may increase the risk of falls. This narrative literature review aims to summarize the existing knowledge on the opioid-related fall risk in older adults, including the pharmacokinetics and pharmacodynamics, and assist clinicians in prescribing and deprescribing opioids in older persons. We systematically searched relevant literature on opioid-related fall risk in older adults in PubMed and Scopus in December 2020. We reviewed the literature and evaluated fall-related adverse effects of opioids, explaining how to optimally approach deprescribing of opioids in older adults. Opioid use increases fall risk through drowsiness, (orthostatic) hypotension and also through hyponatremia caused by weak opioids. When prescribing, opioids should be started with low dosages if possible, keeping in mind their metabolic genetic variation. Falls are clinically significant adverse effects of all opioids, and the risk may be dose dependent and highest with strong opioids. The risk is most prominent in older adults prone to falls. To reduce the risk of falls, both pain and the need for opioids should be assessed on a regular basis, and deprescribing or changing to a lower dosage or safer alternative should be considered if the clinical condition allows. Deprescribing should be done by reducing the dosage gradually and by assessing and monitoring the pain and withdrawal symptoms at the same time. Weighing the risks and benefits is necessary before prescribing opioids, especially to older persons at high risk of falls. Clinical decision tools assist prescribers in clinical decisions regarding (de-) prescribing.

Effects of chronic tramadol administration on cognitive flexibility in mice

RATIONALE

Tramadol is widely used for pain relief especially in seniors. However, long-term use of tramadol has serious adverse effects, including cognitive impairment. Besides its memory effects, already demonstrated in animals, a recent clinical report suggests that tramadol could also affect executive function in seniors. Several studies have hypothesized that the anti-muscarinic properties of tramadol could be responsible for the deleterious effects of tramadol on cognition.

OBJECTIVES

We aimed at investigating the effects of chronic administration of tramadol on cognitive flexibility in adult male mice, as assessed by a visual discrimination reversal task using a touchscreen device. The effects of tramadol were further compared to those of scopolamine, a reference muscarinic antagonist.

RESULTS

We found that, during the early phase of the reversal task, when cognitive flexibility is most in demand, both tramadol-treated mice (20 mg/kg, s.c., twice a day) and scopolamine-treated mice (0.5 mg/kg, s.c., twice a day) needed more correction trials and showed a higher perseveration index than saline-treated mice. Therefore, tramadol affects cognitive flexibility, and its anticholinergic properties could be at least partly involved in these deficits.

CONCLUSIONS

In view of these deleterious cognitive effects of tramadol, physicians should be cautious when prescribing this analgesic, especially in seniors who are more vulnerable to adverse drug events and in which alternative prescription should be preferred whenever possible.

CYP2D6-inhibiting drugs and risk of fall injuries after newly initiated antidepressant and antipsychotic therapy in a Swedish, register-based case-crossover study

Drug-drug interactions have been shown to affect the risk of fall injuries when opioids are used concomitantly with drugs inhibiting the cytochrome P450 2D6 (CYP2D6) enzyme in a previous pharmacoepidemiological study. The aim of this study was to determine whether CYP2D6-inhibiting drugs reinforce the risk of fall injuries when used concomitantly with antidepressants or antipsychotics. We identified all 252,704 adults with a first fall injury leading to hospitalisation from the National Patient Register in Sweden 2006–2013. Data on dispensed drugs was linked from the Swedish Prescribed Drug Register. We applied a case-crossover design to analyse newly dispensed (28 days preceding the fall injury, preceded by a 12-week washout period) antidepressants and antipsychotics, respectively, in relation to risk of a fall injury and according to concomitant use of CYP2D6-inhibiting drugs. Newly dispensed drugs were assessed correspondingly in a control period of equal length, 28 days prior to the 12-week washout period. Overall, the risk of fall injury was increased after newly initiated antidepressant and antipsychotic treatment. For antidepressants, concomitant CYP2D6 inhibitor use further elevated the risk estimates compared to non-use, most pronounced for the groups selective serotonin reuptake inhibitors (sertraline excluded) [OR = 1.47 (95% CI 1.19–1.80) vs. OR = 1.19 (95% CI 1.13–1.26)], and tricyclic antidepressants [OR = 1.71 (95% CI 1.17–2.51) vs. 1.27 (95% CI 1.11–1.47)] as well as for sertraline [OR = 1.61 (95% CI 1.05–2.38) vs. 1.12 (95% CI 1.00–1.26)]. For antipsychotics, the risk of fall injury was not altered by concomitant use of CYP2D6-inhibiting drugs. In conclusion, concomitant use of CYP2D6 inhibiting drugs tends to further increase the risk of fall injury in newly initiated antidepressant treatment, but not in antipsychotic treatment.

Regional Differences in Opioid Prescribing in Germany - Results of an Analysis of Health Insurance Data of 57 Million Adult People

Background

Regional variations of opioid use have been reported from many countries. The objective of this study was to examine opioid prescribing patterns in Germany including low- and high-potency opioids (LPO and HPO) focusing on regional differences.

Methods

Data source was the "Information system for health care data" comprising statutory health insurance funds data for about 70 million Germans of all ages. For 2010, we received aggregated data (by age, sex, federal state and district) of Germans (18+) who had been prescribed at least one opioid including the number of prescribed packages. For each stratum, we further received the number of insured persons. We calculated LPO and HPO prevalences and the mean number of prescribed packages.

Results

Among 57 million adult Germans (mean age: 50.2 years, 53.8% female), opioid prevalences were 38.7 per 1000 persons for LPOs and 12.8 for HPOs. Prevalences rose with increasing age and were higher in women than in men. On average, LPO users were prescribed fewer packages than HPO users (3.5 vs 7.0). LPO use was highest in the eastern states ranging from 32.9 per 1000 persons (Hamburg) to 47.2 (Saxony-Anhalt). HPOs were most often prescribed in the North and in the East with prevalences varying between 10.6 per 1000 persons (Baden-Württemberg) and 16.9 (Mecklenburg-Western Pomerania). On the district level, prevalences varied by the factors 2.6 and 3.2 for LPOs and HPOs, respectively.

Conclusion

We found large regional variations in opioid prescribing which probably cannot only be attributed to differences in patient characteristics.

Association of Tramadol Use With Risk of Hip Fracture

Several professional organizations have recommended tramadol as one of the first-line or second-line therapies for patients with chronic noncancer pain and its prescription has been increasing rapidly worldwide; however, the safety profile of tramadol, such as risk of fracture, remains unclear. This study aimed to examine the association of tramadol with risk of hip fracture. Among individuals age 50 years or older without a history of hip fracture, cancer, or opioid use disorder in The Health Improvement Network (THIN) database in the United Kingdom general practice (2000-2017), five sequential propensity score-matched cohort studies were assembled, ie, participants who initiated tramadol or those who initiated one of the following medications: codeine (n = 146,956) (another commonly used weak opioid), naproxen (n = 115,109) or ibuprofen (n = 107,438) (commonly used nonselective nonsteroidal anti-inflammatory drugs [NSAIDs]), celecoxib (n = 43,130), or etoricoxib (n = 27,689) (cyclooxygenase-2 inhibitors). The outcome was incident hip fracture over 1 year. After propensity-score matching, the included participants had a mean age of 65.7 years and 56.9% were women. During the 1-year follow-up, 518 hip fracture (3.7/1000 person-years) occurred in the tramadol cohort and 401 (2.9/1000 person-years) occurred in the codeine cohort. Compared with codeine, hazard ratio (HR) of hip fracture for tramadol was 1.28 (95% confidence interval [CI] 1.13 to 1.46). Risk of hip fracture was also higher in the tramadol cohort than in the naproxen (2.9/1000 person-years for tramadol, 1.7/1000 person-years for naproxen; HR = 1.69, 95% CI 1.41 to 2.03), ibuprofen (3.4/1000 person-years for tramadol, 2.0/1000 person-years for ibuprofen; HR = 1.65, 95% CI 1.39 to 1.96), celecoxib (3.4/1000 person-years for tramadol, 1.8/1000 person-years for celecoxib; HR = 1.85, 95% CI 1.40 to 2.44), or etoricoxib (2.9/1000 person-years for tramadol, 1.5/1000 person-years for etoricoxib; HR = 1.96, 95% CI 1.34 to 2.87) cohort. In this population-based cohort study, the initiation of tramadol was associated with a higher risk of hip fracture than initiation of codeine and commonly used NSAIDs, suggesting a need to revisit several guidelines on tramadol use in clinical practice. © 2020 American Society for Bone and Mineral Research.

Treatment With Bupropion and Varenicline for Smoking Cessation and the Risk of Acute Cardiovascular Events and Injuries: a Swedish Case-Crossover Study

Introduction

Bupropion and varenicline are non-nicotine medications used for smoking cessation that mitigate craving and withdrawal symptoms. We aim to investigate whether these drugs increase the risk of selected acute adverse outcomes when used in medical practice.

Methods

Population-based case-crossover design using data from Swedish health and administrative registers. Adult individuals diagnosed with acute myocardial infarction, stroke, suicide, suicide attempt, fall injury, or that suffered a road traffic crash from 01.10.2006 for bupropion, or from 01.03.2008 for varenicline, until 31.12.2013 were included. Different lengths of exposure periods were analyzed within the 12-week hazard period prior to the adverse outcome (1-14, 15-28, and 29-84 days). The control period was matched using the interval preceding the hazard period (85-168 days), and breaking it up into equivalent periods (85-98, 99-112, and 113-168 days). Conditional logistic regression with each case considered as one stratum was used to estimate adjusted odds ratios (OR) and confidence intervals (CI).

Results

Neither medication was associated with consistent higher risks for any of the adverse outcomes. For bupropion and varenicline, respectively, in the 1-14 days hazard period, OR (95% CI) were: myocardial infarction 1.14 (0.55 to 2.34) and 1.06 (0.70 to 1.62); stroke 1.16 (0.39 to 3.47) and 1.26 (0.72 to 2.17), and traffic crashes 0.85 (0.39 to 1.85) and 1.48 (0.90 to 2.41). In the other periods, ORs were similar or even lower. For falls and suicidal events ORs were generally below one for both drugs.

Conclusion

The available evidence suggests that if prescription guidelines are properly followed regarding potential contraindications both of these medications could be considered relatively safe.

Implications

The reliable exposure and diagnosis assessment used in this nationwide register-based study, along with the number of cases gathered makes this sample one of the largest of its type to assess potential side effects associated with the use of these drugs. Neither medication was associated with consistent higher risks for any of the adverse outcomes studied.

Endogenous Opiates and Behavior: 2016

This paper is the thirty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2016 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.