Is “Non-Traditional” Risk Stacking the Solution for Pneumococcal Disease? Special ID Week 2018 Public Health Watch

Risk for reward.

A slight variation on an old cliché may hold a key for improving outcomes in pneumonia—if some new findings presented this week at ID Week 2018, taking place in San Francisco, California, are any indication. In fact, a presentation by a team of researchers from Costa Rica suggests that risk assessment for pneumococcal disease may benefit from some out-of-the-box (to use another tired phrase) thinking.

But first some background: In 2010, the Centers for Medicare and Medicaid Services (CMS) introduced the Hospital Readmissions Reduction Program (HRRP) with the stated goal of reducing early readmissions following hospitalizations for common medical conditions. And, at least with regard to pneumonia, the results so far have been mixed. An analysis published on September 28 in the Journal of the American Medical Association (JAMA) revealed that although in-hospital mortality resulting from acute myocardial infarction, heart failure, and pneumonia decreased over an 8-year period (beginning in 2006 and ending in 2014, covering 4 years before and 4 years after inaction of the HRRP), 30-day post discharge mortality actually increased for pneumonia, from 7.6% to 8.6%—although hospital readmissions due to the infection did drop from 17.4% in 2006 to 16.5% in 2014. In all, there were approximately 3.5 million hospitalizations for pneumonia included in the study.

The authors of the JAMA paper write that “there are no clear explanations for this change,” but add that the “increasing complexity of patients may manifest with an increase in early post-discharge mortality, particularly because risk adjustment may not adequately account for all changes in illness severity over time.” Which is where the study presented at ID Week comes in.

The Costa Rican authors of the abstract assessed the “value of nontraditional high-risk factor stacking… for pneumococcal disease in patients seeking care at Social Security Hospitals” in the Central American nation. Looking at 181 adult patients with microbiological culture-positive Streptococcus pneumonia admitted to 2 hospitals, over a 3-year period, they analyzed data on “underlying comorbidities” (non-traditional) and other risk factors for the infectious disease, “stacking” them for each age group (<50 years, 50-64 years, and ≥65 years).

Notably, the investigators found that the majority (63%) of patients under 50 stacked at least 2 risk factors, while 18% of those at age 65 had no other risk factors for pneumonia (beyond their age at the time of admission). The most common risk factors for those under 50 and those between the ages of 50 and 64 were a history of smoking and alcoholism, while the most common risk factors for the older patients in the study were a history of chronic pulmonary and heart diseases.

Although the authors didn’t respond to an email requesting comment, they noted in their concluding remarks “that risk factor stacking is more relevant than high-risk conditions and [that] pneumococcal disease also occurs in persons” younger than 50. Based on their findings, the team recommends that risk factor stacking be considered in prevention strategies for pneumococcal disease.

The presentation echoes the findings of a larger study published in 2015 in the journal Open Forum Infectious Diseases. In that paper, authors from the Boston University Schools of Medicine and Public Health concluded that “adults with ≥2 concurrent comorbid conditions had pneumococcal disease incidence rates that were as high as or higher than rates observed in those with traditional high-risk conditions.”

Given that World Health Organization figures suggest that there are more than 14 million cases of pneumococcal disease globally each year, and that roughly 6% result in death, it could be argued that the time for a different approach to stratifying risk is long overdue.

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous health care-related publications. He is the former editor of Infectious Disease Special Edition.