Antibiotic Prescriptions Spike Before Diagnosis of Health Condition

Respiratory symptoms of conditions like chronic obstructive pulmonary disease (COPD), heart failure, and asthma may be frequently misdiagnosed as an infection, a new study suggests after finding a rapid increase in antibiotic prescribing before diagnosis followed by a decline after diagnosis.

The study, published in Clinical Infectious Diseases, looked at health records of more than 100,000 adults in the United Kingdom between 2008 and 2015 with new-onset stroke, coronary heart disease, heart failure, peripheral arterial disease, asthma, chronic kidney disease, diabetes or COPD. Investigators examined antibiotic prescribing rates before and after diagnosis.

“Antibiotic use increases a lot in the months before patients are diagnosed with COPD, asthma and heart failure. This could be because these conditions are being misdiagnosed as respiratory infections,” Laura Shallcross, PhD, consultant in public health medicine at the Institute of Health Informatics at University College London, told Contagion^®.

Noting that such conditions increase susceptibility of infection, the investigators found that patterns of antibiotic prescribing revealed another trend.

“We anticipated that antibiotic use would increase after patients had been diagnosed with comorbidity, and were surprised to see this clear pattern of increased antibiotic prescribing before diagnosis for COPD, asthma and heart failure and to a lesser extent for diabetes,” Shallcross said.

Patients with asthma, heart failure and COPD were most likely to receive antibiotics before diagnosis, with prescribing rates doubling (1.9 to 2.3 times) in the 4 to 9 months before diagnosis and leveling off after diagnosis, the study found. Those with diabetes saw a 1.48—1.61-fold increase in the rate of antibiotic prescriptions before diagnosis. Patients with vascular conditions were most likely to see higher antibiotic levels after diagnosis, with rates remaining 30% to 39% higher.

“Increased frequency of antibiotic prescribing in primary care could be a warning sign for undiagnosed comorbidities that present with respiratory symptoms,” Shallcross told Contagion^®.

The study noted that an alternative explanation for this spike in antibiotic prescriptions could be that repeat infections may trigger the onset of chronic conditions and that it is difficult to determine whether the prescription rates reflect genuine bacterial infections, mistreatment of viral infections or misdiagnosis of the symptoms chronic disease.

Limitations to available testing to diagnose chronic diseases is a challenge, with the study said, noting that the average time between the onset of symptoms and diagnosis is 2.5 years for heart failure and 6-13 years for diabetes. This lag could drive antibiotic overuse and increase the risk of resistance.

“Our findings are based on population-level data. We need to consider how these results can be used to guide individual-level antibiotic prescribing decisions in the clinic,” Shallcross told Contagion^®.

The study reinforces the efforts of some antibiotic stewards who are taking a closer look at noninfectious conditions for which antibiotics should never be prescribed, including asymptomatic bacteriuria and viral upper respiratory tract infections. Such efforts are a vital component to antimicrobial stewardship programs that often focus on improving the quality of antibiotic use through such measures as careful selection of antibiotics and reduction of the duration of treatment.

Antimicrobial-resistant infections are estimated to kill 23,000 Americans annually, with some estimates predicting the total worldwide death toll to reach 10 million worldwide by 2050. Those statistics are behind efforts including recent changes to antibiotic reimbursements from the Centers for Medicare and Medicaid Services.