The disease burden of pertussis in adults 50 years old and older in the United States: a retrospective study

Abstract

BackgroundWhile the incidence of pertussis has increased in adolescents and adults in recent years in the U.S., little is known about the incidence and economic burden of pertussis in older adults. This study provides evidence of the incidence of pertussis and direct medical charges associated with pertussis episodes of care (PEOCs) in adults aged 50 years and older in the U.S.MethodsPEOCs were divided into periods before and after the initial pertussis diagnosis was made (i.e., the index date) to capture any conditions immediately preceding the pertussis diagnosis that may have represented misdiagnoses and subsequent conditions that may have represented sequelae. Data were extracted from IMS's recently acquired SDI databases of longitudinal, patient-level practitioner claims and hospital operational billing records collected from private practitioners and hospitals, respectively, across the U.S. Patients 50 years and older with one or more ICD-9-CM diagnoses for pertussis/whooping cough and/or a laboratory test positive for Bordetella pertussis between 1/1/2006 and 10/31/2010 were eligible for study inclusion. Resource utilization and charges (i.e., unadjudicated claims) associated with the patient's physician and hospital care were analyzed. The nationally projected incidence of pertussis was estimated using a subsample of patients with the required data necessary for projection.ResultsEstimated incidence of diagnosed pertussis ranged from 2.1-4.6 cases per 100,000 people across the two age groups (50–64 and [greater than or equal to] 65) during the years 2006 to 2010. The analysis of charges included 5,748 patients [greater than or equal to] 50 years of age with pertussis. Average charges across the entire episode of care were $1,835 and $14,428 per patient in the outpatient and inpatient settings, respectively. The average number of outpatient (i.e., private practitioner) visits was 2 per patient in both the pre-index and post-index periods.ConclusionsIn the U.S., the incidence of diagnosed pertussis in adults 50 years and older has increased between 2006 and 2010. Healthcare utilization and charges associated with pertussis are substantial, suggesting the need for additional prevention and control strategies and a higher degree of clinical awareness on the part of health care providers. Additional research regarding pertussis in older populations is needed to substantiate these findings.

Attitude of Italian physicians toward pertussis diagnosis

“…9 We therefore investigated the attitude of Italian physicians toward suspecting pertussis in the differential diagnosis of prolonged cough and prescribing appropriate laboratory tests for confirmation in different age groups.…”

Prevention of pertussis through adult vaccination

“…7,8 Since the 1980s, there has been a gradual increase in reported pertussis cases in the US, with cyclical peaks observed every 3-4 years, particularly among the adolescents and adults. [9][10][11][12][13][14] In 2012, alone, 48, 277 cases of pertussis were reported to the Centers for Disease Control and Prevention (CDC), the highest number of cases reported in one year since 1955. 15 This resurgence in pertussis, with high pre-school pertussis vaccine coverage, is primarily thought to be due to waning immunity and persistent transmission of infection by adolescents and adults, confirming the need for booster vaccines for this population.…”

“…5,7,11 The importance of pertussis prevention in adults is 2-fold: vaccination programs in this population are a cost effective method to reduce disease-associated morbidity and to decrease possible transmission of infection to young infants who are at risk for severe complications. 13,[17][18][19][20] Vaccine Recommendations was expanded to include adults younger than 65 years, particularly for those in contact with infants younger than 12 months of age. 21,22 Despite this recommendation, by 2008 only 5% of adults were estimated to have received a Tdap vaccine.…”

Pertussis

“…They demonstrate that parents, family members and cohabitants frequently are the source of infection in infants, 74 and suggest that oligo-and asymptomatic patients play an important role in spreading the infection. 75,76 The role of adults in spreading the infection is reinforced by the difficulty in identifying symptoms in this age group; the diagnosis of pertussis is rarely considered in adult patients. 77 Moreover, it should be borne in mind that, besides the mode of transmission, infection dynamics also depends on the number of contacts among individuals in a given population and this parameter is population specific.…”

“…94 In this age group, disease diagnosis is difficult due to non-specific symptoms and probably also to the fact that the healthcare staff perceives this disease as rare in older subjects; 77 however, the proportion of pertussis cases in adults is high. 95,96 Offering adult immunization is not an easy strategy to implement nor is the rapid achievement of vaccine coverage. A booster dose should be administered taking into consideration the time that has elapsed from the previous dose.…”