932. Analysis of Seasonal Variation of Antibiotic Prescribing for Respiratory Tract Diagnoses in Primary Care Practices


 
 
 Seasonal fluctuations in antibiotic prescribing for respiratory tract diagnoses (RTDs) have been identified, but characteristics and appropriateness of these variations have not been well described. The objectives of this study were to describe seasonal variations for RTDs and to determine whether seasonal variation in prescribing is associated with inappropriate use.
 
 
 
 From July 1, 2016 through June 30, 2017, antibiotic prescribing was analyzed for 31 primary care practices comparing winter (October-March) and summer (April-September) months. ICD-10 codes for RTDs were described as tier 1, 2, or 3 based on whether antibiotics are almost always, sometimes, or almost never indicated, respectively. Twenty visits from each of 60 providers were randomly selected and manually reviewed to determine a gold standard of antibiotic appropriateness in order to characterize the appropriateness of these seasonal variations. Associations between season and diagnosis tier, season and appropriateness, and individual provider seasonal changes in antibiotic prescribing and provider characteristics were determined.
 
 
 
 There was a lower proportion of visits with tier 3 diagnoses in winter months (68% v. 74%, p< 0.01), but a greater proportion of tier 2 diagnoses (29% v. 23%, p< 0.01). There were greater proportions of visits in which an antibiotic was prescribed for both tier 2 (80% vs 74%, p< 0.01) and tier 3 diagnoses (23% v. 16%, p< 0.01) in winter months. Using medical record review, inappropriate antibiotics were prescribed more frequently for RTDs in winter compared to summer months (73% v. 64%, p< 0.01). Greater individual provider difference in proportion of RTD visits in which an antibiotic was prescribed from summer to winter was associated with family medicine v. internal medicine specialty (8.2% v. 5.1%, p< 0.01), nonteaching v. teaching practice (8.1% v. 2.9%, p< 0.01), and nonurban v. urban setting (9.1% v. 3.9%, p< 0.01).
 
 
 
 Although there was a greater proportion of tier 2 compared to tier 3 RTDs in winter months, winter months were associated with more inappropriate prescribing than in summer months. More investigation is needed to understand the drivers for seasonal variations in RTDs and inappropriate prescribing.
 
 
 
 Kathleen Degnan, MD, Gilead: Grant/Research Support Michael Z. David, MD PhD, Contrafect: Grant/Research Support|GSK: Advisor/Consultant|Johnson and Johnson: Advisor/Consultant.
