Study: Warmer Weather Increases Likelihood of Surgical Infections

By on 3:07 PM

A new study indicates that warmer temperatures are tied to an increase in surgical site infections (SSIs).

The study is titled "The Seasonal Variability in Surgical Site Infections and the Association With Warmer Weather: A Population-Based Investigation" and published in Infection Control & Hospital Epidemiology. It examined hospital discharges with a primary diagnosis of SSI from 1998 to 2011 extracted from the Nationwide Inpatient Sample (this database is maintained as part of AHRQ's Healthcare Cost and Utilization Project and contains data from a 20% stratified sample of nonfederal acute-care hospitals).

The study also used data from the National Climatic Data Center to estimate monthly average temperatures for hospital locations.

The researchers determined that, "SSI incidence is highly seasonal, with the highest SSI incidence in August and the lowest in January. During the study period, there were 26.5% more cases in August than in January."

The odds of a primary SSI admission increased by roughly 2% per 5°F increase in the average monthly temperature. The highest temperature group of greater than 90°F was associated with a nearly 30%  increase in the odds of an SSI admission compared to below 40°F.

The researchers concluded the following: "At population level, SSI risk is highly seasonal and is associated with warmer weather."

Note: Infection Control Consulting Services (ICCS) consultants frequently deal with issues in surgery suites that relate to temperature and humidity control, particularly in hot and humid climates such as Florida. Several ambulatory surgery centers, often situated in older buildings, have reached out asking whether portable air conditioning units and dehumidifiers can be placed in the operating rooms. ICCS advises clients to follow nationally recognized guidelines and standards, including AORN, ASHRAE and ANSI/AAMI, when making decisions that will or have the potential to effect patient care and safety. 



  1. It would be interesting to see if the seasonal pattern is the opposite in the southern hemisphere. If so, that would give some added support to these findings.

  2. Good point Michael. We'll keep an eye out for this. Thanks for commenting.