Pertussis, or "whooping cough", is a highly contagious infection of the respiratory tract that is most dangerous for infants. After the introduction of the pertussis vaccine in the 1940s, the disease decreased substantially. Between the years 2011 and 2012, there was an outbreak of pertussis in the United Kingdom (UK). Following this outbreak, a pertussis vaccination programme was introduced for pregnant women. The diphtheria, tetanus, pertussis and polio (dTaP-IPV) vaccine is given to pregnant women to protect young babies against pertussis until they can be vaccinated at eight weeks old. Although pertussis is generally milder in adults, information on the frequency and risk factors for pertussis among adults is limited. It is important to understand the real-world burden and cost of general practitioner and hospital resources required to treat adults with pertussis as well as the clinical outcomes for these patients.
This feasibility study aims to understand availability and completeness of data relating to pertussis and clinical and economic outcomes in adults in the UK from 2012 to 2019. Results of this study will help inform whether the Clinical Practice Research Datalink is a suitable data source to complete a full study to investigate the frequency, risk factors, vaccination rates, clinical outcomes, and healthcare utilization and cost in adults with pertussis.
This study investigates the availability and completeness of data on pertussis and corresponding clinical and economic outcomes in the UK adult population from 2012 to 2019. Study objectives are:
1. Determine and describe the number of diagnosed and clinically suspected pertussis patients among the adult population.
2. Describe age distribution of diagnosed pertussis incidence during the study period in patients aged 18-44,45-64, and 65+ years.
3. Describe demographic and clinical characteristics of patients with diagnosed pertussis.
4. Describe the number of pertussis confirmatory laboratory requests among adults with/without asthma, chronic obstructive pulmonary disease (COPD) and asthma and COPD.
5. Describe the number of pertussis vaccinations (Diphtheria, Tetanus, acellular Pertussis [dTaP-IPV]) overall and in a female cohort by pregnancy status.
6. Describe asthma and COPD exacerbations associated with a pertussis episode.
7. Describe patient hospital admissions with pertussis as the primary diagnosis.
8. Describe patient hospital inpatient admissions, accident and emergency visits and outpatient clinic visits 1 year prior to and post a pertussis episode.
9. Describe patients’ levels of frailty using electronic frailty index with deficit counts and frailty status, prior to and post index in 18-64 and 65+ age groups at 12, 24, and 60 months.
This will be a retrospective comparative cohort study using CPRD Aurum linked to HES (objectives 6-8) and Index of Multiple Deprivation (objective 3) data sources. The overall study population will include patients aged 18+ years, with a diagnosis of pertussis during the study period. Descriptive analyses will be conducted using number and percent with mean, median, and other summary statistics for continuous variables. No imputation methods will be used. Findings inform the full study and benefit patients in England and Wales by informing public health policy regarding the burden of pertussis in adults with downstream benefits to healthcare outcomes for the general population.
• Variables to define the study population: Pertussis diagnosis; Clinical diagnosis or symptoms associated with pertussis test referral; Confirmatory pertussis test referral
• Patient demographic and clinical characteristics: Age; Sex; Ethnicity; Geographic region; Deprivation score (IMD); Smoking Status; Asthma diagnosis; Chronic obstructive pulmonary disease (COPD) diagnosis; Asthma and COPD diagnosis (ACOS); Type 1 diabetes mellitus diagnosis; Type 2 diabetes mellitus diagnosis; Obesity; Immunocompromising conditions diagnoses; Chronic neurological disorder diagnosis; Cardiovascular disease diagnosis
• Availability and completeness in Clinical Practice Research Datalink (CPRD): Laboratory confirmation request; Pertussis vaccination; Pregnancy status; Electronic frailty index (eFI) score; eFI score deficits; Asthma exacerbation; COPD exacerbation
• Availability and completeness in Hospital Episode Statistics (HES): Inpatient hospitalisation due to pertussis; Outpatient visits due to pertussis; Accident and Emergency (A&E) visits due to pertussis; Inpatient hospitalization; Outpatient visits; A&E visits; Asthma exacerbation; COPD exacerbation
Rachel Armstrong - Chief Investigator - IQVIA Ltd ( UK )
Molebedi Segwagwe - Corresponding Applicant - IQVIA Ltd ( UK )
Briana Coles - Collaborator - IQVIA Ltd ( UK )
Mariane Fontanelli - Collaborator - IQVIA - USA (Headquarters)
Xiaohui Sun - Collaborator - IQVIA Ltd ( UK )
Zheyuan Yang - Collaborator - IQVIA Ltd ( UK )
Eleanor Ralphs - Collaborator - IQVIA Ltd ( UK )
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;Patient Level Index of Multiple Deprivation