Morbidity of community-acquired pneumonia

Baskaran, Vadsala (2021) Morbidity of community-acquired pneumonia. PhD thesis, University of Nottingham.

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Abstract

Background

Community-acquired pneumonia (CAP) accounts for 5-12% of lower respiratory tract infections presenting to primary care in the UK. Of patients who present to their GP with suspected CAP, 22- 42% are referred to hospital for further management in the UK. The majority of patients ( ̴90%) admitted for CAP survive to hospital discharge. However, little is known about the morbidity related to recovery from pneumonia.

Methods

Three studies in this thesis used large-scale hospitalisation data from Hospital Episode Statistics (HES, England), linked to the Clinical Practice Research Datalink (CPRD), and death registration data from Office for National Statistics (ONS). These studies aim to improve our understanding on the morbidity after CAP and the objectives were:

(1) to describe the primary care consultations after pneumonia and the reasons for these consultations

(2) to determine the incidence of, and risk factors for developing cardiac complications

(3) to determine the incidence of recurrent hospitalisation for pneumonia and the association of tobacco smoking.

In addition, published literature on cardiac complications, a major morbidity following CAP and tobacco smoking and passive smoke exposure as a risk factor for developing CAP were systematically summarised.

Finally, a multicentre retrospective study was conducted during the first wave of COVID-19 pandemic to determine the proportion of laboratory proven co-infection in critically ill adults with COVID-19 infection in England.

Results

This thesis found a previously unrecognised large burden of morbidity during recovery from pneumonia; 56% of patients consulted primary care within 30 days of discharge. The highest rate of consultation occurred early, within the first 7 days (4.7 per 100 person-days). Nearly 40% of consultations were for a respiratory disorder and 30% of patients consulting received further antibiotics within 30 days of discharge.

The systematic review (n=47 studies) found an in-hospital incidence of cardiac complications of between 3-8%. Patients who developed cardiac complications were more likely to die both in-hospital (odds ratio (OR) 3.45, 95% CI 2.38-4.99) and within 30 days (OR 2.65, 95% CI 1.24-5.68) of admission than those who did not. Data from the population-based study showed that those with pneumonia were significantly at higher risk of developing all cardiac complications compared to those without pneumonia. The highest risk was observed for developing arrhythmia at 30 days after discharge (subhazard ratio (sHR) 9.51, 95% CI 8.35-10.83).

The systematic review (n=27 studies) found that current and ex-smokers were both significantly at higher risk of developing CAP whilst passive tobacco smoke exposure had a significant effect only in those aged ≥ 65. A dose-response trend with higher risk of CAP amongst current smokers who smoke higher amounts of tobacco was noted. From the population-based study, 9% of patients hospitalised with index pneumonia developed recurrent pneumonia within a year of follow-up. Current tobacco smoking status at index hospitalisation for pneumonia was independently associated with a higher risk of recurrent pneumonia.

Finally, bacterial co-infection within 48 hours of hospital admission for COVID-19 infection in adults was uncommon; 1.6% on admission and 5.5% within 48 hours. Patients with co-infections were more likely to die in ICU (crude OR 1.78, 95% CI 1.03-3.08) compared to those without co-infections.

Conclusion

In conclusion, this thesis highlights that patients experience significant morbidity during recovery from pneumonia. A better understanding of the morbidity after CAP is necessary to develop and implement appropriate interventions to improve the long-term outcomes of patients hospitalised with CAP.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: McKeever, Tricia
Lim, Wei Shen
Keywords: Morbidity, Pneumonia, Cardiac complications, Smoking, COVID
Subjects: W Medicine and related subjects (NLM Classification) > WC Communicable diseases
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Medicine
Item ID: 65726
Depositing User: Baskaran, Vadsala
Date Deposited: 04 Aug 2021 04:43
Last Modified: 04 Aug 2021 04:43
URI: http://eprints.nottingham.ac.uk/id/eprint/65726

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