Study: Financial incentives cut antibiotic use but not resistance

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A UK program offering financial incentives for reducing primary care antibiotic use was found to have a positive impact on prescribing but less of an effect on antibiotic resistance rates, according to a study this week in The Lancet Infectious Diseases.

The study, led researchers from Imperial College London, England's National Health Service (NHS), and Public Health England (PHE), evaluated the impact of the Quality Premium, a program that provides performance-related rewards each year to Clinical Commissioning Groups (CCGs) for improvements in healthcare service quality. All hospitals and primary care practices in England belong to CCGs, which are responsible for the quality of the healthcare in each area of the country.

After the Quality Premium added its antimicrobial stewardship reward in 2015, the researchers found that outpatient antibiotic use declined but the long-term impact on antibiotic resistance was negligible. Resistance did fall slightly after implementation; however, it remained on an upward trajectory overall.

"This study suggests that reducing prescribing might be insufficient as a standalone strategy to curtail antimicrobial resistance in the primary care setting, although it is effective in attenuating trends in resistance," the study authors wrote.

Long-term trends in resistance unchanged

The researchers assessed the intervention by conducting an interrupted time series analysis using longitudinal data on prescribing data of five antibiotics commonly used for community infections (co-amoxiclav, levofloxacin, ciprofloxacin, moxifloxacin, and oflofloxacin) and resistance in human bloodstream infections (bacteremia) caused by Escherichia coli. The study covered 6,882 general practitioner (GP) practices from 2013 through 2018—27 months prior to program implementation and 45 months after. It also used antimicrobial susceptibility data collected by PHE.

The analysis found that the rate of prescribing for all five broad-spectrum antibiotics was increasing by 0.2% per month before the Quality Premium intervention began (incidence rate ratio [IRR], 1.002; 95% confidence interval [CI], 1.000 to 1.004). After implementation, though, an immediate reduction was observed (IRR, 0.867; 95% CI, 0.837 to 0.897), which was sustained until the end of the study period.

The overall effect was a 57% decrease in total antibiotic prescribing compared with what the rate would have been without the program. The decline was driven primarily by reduced prescribing of co-amoxiclav, the most commonly prescribed antibiotic in GP practices.

As for bacteremia-causing E coli, resistance rates to at least one antibiotic rose by 0.1% per month prior to the intervention (IRR, 1.001; 95% CI, 0.999 to 1.003) but immediately declined after it was implemented (IRR, 0.947; 95% CI, 0.918 to 0.977)—a 12.03% reduction compared with resistance rates with no intervention.

However, an adjusted analysis accounting for antibiotic prescribing, age, comorbidities, deprivation index, and geographical region found little effect on total resistance to broad-spectrum antibiotics (IRR, 0.996; 95% CI, 0.987 to 1.005). And in the long-term, there was a sustained increase in the number of E coli isolates resistant to at least one of the antibiotics tested (IRR, 1.002; 95% CI, 1.000 to 1.003).

"The overall pattern was one of attenuation rather than a reversal of previously rising rates of antibiotic-resistant E coli isolates, with the pre-intervention increase in rates of antibiotic resistance persisting in the long term," the authors wrote.

Multisectoral effort may be needed

The authors note that while many studies on antibiotic stewardship interventions focus on changes in the antibiotic prescribing rate, studying the effect of such interventions on resistance rates is important for quantifying the impact reduced prescribing ultimately has on resistance trends.

"To advance understanding of the effect of antimicrobial stewardship interventions on antibiotic resistance and the resulting implications for policy and practice, assessment of both antimicrobial prescribing and antibiotic resistance data is necessary," they wrote.

They suggest that, as some research has indicated, it may take many years for a decrease in antibiotic prescribing to reduce corresponding resistance. But they also contend that resistance may continue to rise, despite reduced antibiotic use, because bacteria are accumulating resistance mutations and acquiring resistance genes from other bacterial species. Furthermore, antibiotic use in food-producing animals may be promoting the emergence of resistance genes that can be transmitted to humans through the food chain.

In a commentary that accompanies the study, US clinicians from the National Institutes of Health Clinical Center say that despite the findings on resistance, the success of the Quality Premium should not be overlooked and that reductions in antibiotic consumption, and cost may be more appropriate measures for outpatient antibiotic stewardship measures. They suggest that similar financial incentive programs, while not feasible in every country, could be part of a broader, multisectoral effort to combat resistance.

"A so-called one-health approach that integrates human and veterinary medicine and other sectors, national leadership, and international coordination is now a well recognised necessity for combating resistance," they wrote. "Perhaps incentivising health-care practice organisations that meet prespecified targets for reduced antibiotic use could represent one component of comprehensive national action programmes in countries that can afford to offer such incentives."

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