Does Transient Opioid Use Increase Risk of Short-Term Respiratory Exacerbation among Older Adults with Chronic Obstructive Pulmonary Disease?

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.

Predictors of Multiwave Opioid Use Among Older American Adults

Background and Objectives

Despite limited analgesic benefits, long-term opioid therapy (L-TOT) is common among older adults with chronic pain. Extended opioid use poses a threat to older adults as aging metabolisms retain opioids for longer, increasing the risk of injury, overdose, and other negative health outcomes. In contrast to predictors of general opioid use, predictors of L-TOT in older adults are not well documented. We aimed to identify such predictors using all available data on self-reported opioid use in the Health and Retirement Study.

Research Design and Methods

Using 5 waves of data, respondents (N = 10,713) aged 51 and older were identified as reporting no opioid use (n = 8,621), a single wave of use (n = 1,410), or multiple waves of use (n = 682). We conducted a multinomial logistic regression to predict both single- and multiwave opioid use relative to no use. Demographic, socioeconomic, geographic, health, and health care-related factors were included in our model.

Results

Multivariable findings show that, relative to nonusers, both single- and multiwave users were significantly more likely to be younger (relative risk ratio [RRR] = 1.33; RRR = 2.88); report lower household wealth (RRR = 1.47; RRR = 2.88); live in the U.S. Midwest (RRR = 1.29; RRR = 1.56), South (RRR = 1.34; RRR = 1.58), or West (RRR = 1.46; RRR = 2.34); experience interfering pain (RRR = 1.59; RRR = 3.39), back pain (RRR = 1.35; RRR = 1.53), or arthritic pain (RRR = 1.46; RRR = 2.32); and see the doctor frequently (RRR = 1.50; RRR = 2.02). Multiwave users were less likely to be Black (RRR = 0.69) or Hispanic (RRR = 0.45), and less likely to be never married (RRR = 0.52).

Discussion and Implications

We identified demographic, socioeconomic, geographic, and health care-related predictors of chronic multiyear opioid use. Our focus on individuals taking opioids for this extended duration is novel. Differences in opioid use by geographic region and frequency of doctor visits particularly warrant attention from policy-makers and researchers. We make additional recommendations based on a sensitivity analysis limited to 2016-2020 data.