Epidemiology of Pneumococcal Disease in a National Cohort of Older Adults

Abstract

IntroductionStreptococcus pneumoniae is a major cause of morbidity and mortality. We sought to describe the epidemiology of non-invasive and invasive pneumococcal disease in a national Veterans Affairs population within the United States.MethodsWe conducted a retrospective study in older patients (aged ≥50 years) with positive pneumococcal cultures from any site between 2002 and 2011. We described outpatient and inpatient pneumococcal disease incidence per 100,000 clinic visits/hospitalizations. Repeat cultures within a 30-day period were considered to represent the same episode. To describe the epidemiology of serious pneumococcal infections (bacteremia, meningitis, pneumonia), we assessed demographics, clinical characteristics, and risk factors for S. pneumoniae. Pneumonia was defined as a positive respiratory culture with a pneumonia diagnosis code. Bacteremia and meningitis were identified from positive cultures. Generalized linear mixed models were used to quantify changes over time.ResultsOver the study period, we identified 45,983 unique episodes of pneumococcal disease (defined by positive cultures). Incidence decreased significantly by 3.5% per year in outpatients and increased non-significantly by 0.2% per year in inpatients. In 2011, the outpatient and inpatient incidence was 2.6 and 328.1 infections per 100,000 clinic visits/hospitalizations, respectively. Among inpatients with serious infections, chronic disease risk factors for pneumococcal disease increased significantly each year, including respiratory disease (1.9% annually), diabetes (1.3%), and renal failure (1.0%). Overall, 30.2% of inpatients with serious infections had a pneumococcal immunization in the previous 5 years. Invasive disease (37.4% versus 34.9%, P = 0.004) and mortality (14.0% versus 12.7%, P = 0.045) were higher in non-vaccinated patients compared to vaccinated patients.ConclusionsIn our national study of older adults, the baseline health status of those with serious pneumococcal infections worsened over the study period. As the population ages and the chronic disease epidemic grows, the burden of pneumococcal disease is likely to increase thus highlighting the importance of pneumococcal vaccination.Electronic supplementary materialThe online version of this article (doi:10.1007/s40121-014-0025-y) contains supplementary material, which is available to authorized users.

Epidemiology of Meningitis Studied at a University Hospital in Zahedan, South-Eastern Iran

“…Risk factors for meningitis include: skipping vaccinations, age (most cases of viral meningitis occur in children younger than five years old and bacterial meningitis commonly affects people under 20), living in a community setting (college students living in dormitories, personnel on military bas-es, and children in boarding schools and child care facilities are at increased risk of meningococcal meningitis), and factors that may compromise patients' immune system including; AIDS, use of immunosuppressant drugs, and removal of the spleen (3-6). There are many reports about the epidemiology of meningitis and according to the community under study, age of cases and other risk factors, agents and clinical outcome are different (8)(9)(10)(11)(12)(13)(14)(15)(16)). …”

Predictors of Mortality Among U.S. Veterans With Streptococcus Pneumoniae Infections

“…[25][26][27] Despite the established benefits of pneumococcal vaccination, multiple studies have identified that current pneumococcal vaccination rates are far below the Healthy People 2020 goals. 11,28 In 2013, the National Health Interview Survey indicated that approximately 67 million at-risk individuals in the U.S. have not received pneumococcal vaccination, placing them at an increased risk of worse outcomes and more severe pneumococcal infection. 5,29 This is concerning, as previous research has demonstrated that people with ACIP indications for pneumococcal vaccination are twice as likely to die as those without indications if they develop invasive pneumococcal disease.…”

“…The Veterans Affairs databases have been described previously. 11,12 An analytic database was created from numerous Veterans Affairs databases capturing patient care, including demographics, inpatient stays, outpatient visits, pharmacy dispensings and administrations, health factors, surgeries and procedures, laboratory and microbiology results, immunizations, and vital status.…”

“…11 Adults aged ≥50 years were selected as they are at the highest risk of developing these serious pneumococcal infections. 5 Positive S. pneumoniae sputum, blood, and cerebrospinal fluid cultures were identified using microbiology datas.…”

“…5 Positive S. pneumoniae sputum, blood, and cerebrospinal fluid cultures were identified using microbiology datas. 11 Pneumonia was identified by positive sputum culture in addition to a pneumonia ICD-9 diagnosis code. From this cohort, individuals who had not received the pneumococcal vaccine, as determined from pharmacy, procedure, and immunization status data, within 5 years of the positive culture were selected for inclusion.…”