Risk factors for hospital readmissions in pneumonia patients: A systematic review and meta-analysis

Table 1 Characteristics of the studies included (n = 17)

No.	Ref.	Country	Study design	Sample size	Mean age (in years)	Study participants	Risk factors reported
1	Ahmedani et al[33], 2015	United States	Retrospective analysis of data	72438	NR	All health plan patients at the participating health systems with an index inpatient hospitalization for pneumonia between January 2009 and December 2011	Dementia
2	Buja et al[36], 2020	Italy	Retrospective cohort study	6258	NR	Residents aged ≥ 65 yr with diagnosis related groups pneumonia (DRG 89 or 90)	Gender
3	Chakrabarti et al[22], 2021	United Kingdom	Retrospective analysis of data	10366	73	All community acquired pneumonia cases submitted by the nine participating hospitals in the AQ Pneumonia Programme between January 1, 2017 and March 31, 2019	Gender, Dementia, Heart failure, Cancer, CRD, CKD, DM, IHD, Cerebrovascular disease
4	Dharmarajan et al[29], 2013	United States	Retrospective analysis of data	214239	NR	Hospitalizations among patients 65 yr or older with a complete claims history for 1 yr preceding admission	Gender
5	Dong et al[30], 2017	United States	Retrospective cohort study	2892	61	Medical records of all 2892 patients coded with a principal diagnosis of pneumonia admitted to the University of Chicago	Age, Gender, Cancer, Heart Failure, CKD, CRD, Cerebrovascular disease
6	Faverio et al[31], 2020	Italy	Retrospective cohort study	203768	71.2	NHS eligible residents in Lombardy who had experienced at least one hospital admission with pneumonia as primary or secondary diagnosis during the years 2003 to 2012	Gender, Cancer, CKD, CRD, CLD, Cerebrovascular disease, Mechanical ventilation
7	Graversen et al[23], 2020	Denmark	Retrospective analysis of data	298564	NR	All Danish residents aged 65-99 yr, who had been discharged after a pneumonia-related hospital admission, referred to as index admission, during our study period	Gender, Dementia, Heart failure, Cancer, CRD, DM
8	Graversen et al[24], 2021	Denmark	Retrospective analysis of data	298872	NR	All Danish citizens aged 65–99 yr, who were discharged after a hospital admission (index admission) with a primary or secondary diagnosis of pneumonia as defined by the allocation of diagnostic codes (ICD-10: J12-J18, A709, or A481)	Dementia
9	Jain et al[34], 2018	United States of America	Retrospective analysis of data	1472070	68.9	All adults discharged alive after a hospitalization with the primary diagnosis of pneumonia	Age
10	Jang et al[35], 2020	Korea	Retrospective cohort	862	68.5	Patients with community acquired pneumonia hospitalized at Yeungnam University Hospital from March 2012 to February 2014	Age, Gender, Dementia, Heart failure, Cancer, CRD, DM, CKD, CLD, Cerebrovascular disease, ICU admission, Mechanical ventilation
11	Knox[32], 2019	United States	Retrospective analysis of data	389956	79	Pneumonia patients ranging in age from 65 to 90 yr of age	Dementia
12	Lee et al[25], 2017	Republic of Korea	Retrospective cohort	7446	NR	Patients older than 65 yr who were hospitalized with pneumonia between 2003 and 2013	Gender, Dementia, Heart failure, Cancer, CRD, CKD
13	Mather et al[11], 2013	United States	Retrospective cohort	956	NR	Adult patients admitted to Hartford Hospital from January 2009 to March 2012 with principal diagnosis of pneumonia (International Classification of Diseases, 9th Revision, Clinical Modification codes 480.XX, 481, 482.XX, 483.X, 485, 486, and 487.0) as potential index pneumonia admission	Gender, Dementia, Heart failure, Cancer, CRD, CKD, DM, IHD
14	Nagasako et al[27], 2014	United States	Retrospective analysis of data	29849	NR	Hospital readmissions for patients discharged from non-federal Missouri acute care or critical access hospitals between June 1, 2009 and May 31, 2012, with principal diagnoses of pneumonia	Gender
15	Shams et al[28], 2014	United States	Retrospective cohort	1306	68.3	Adult patients with principal (or secondary) discharge diagnoses of pneumonia	Gender, Cancer, Heart Failure, CRD, DM, IHD
16	Shorr et al[12], 2013	United States	Retrospective cohort	771	60	All adult subjects with bacterial pneumonia admitted to a single institution between January and December 2010	Gender, Cancer, Dementia, Heart Failure, ICU admission, Mechanical ventilation, Cerebrovascular disease, CRD, DM, IHD
17	Toledo et al[26], 2018	Spain	Cross-sectional	1756	NR	Patients included were aged ≥ 65 yr admitted through the emergency department to any of the participating hospitals for ≥ 24 h with a chest X ray showing pulmonary infiltrate compatible with pneumonia and ≥ 1 of the following symptoms or signs of acute lower respiratory tract infection: Cough, pleural chest pain, dyspnoea, fever > 38 °C, hypothermia < 35 °C and abnormal auscultator respiratory sounds unexplained by other causes	Gender, Heart failure, Cancer, CRD, CKD, DM

NR: Not reported; CRD: Chronic respiratory diseases; CKD: Chronic kidney disease; CLD: Chronic liver disease; DM: Diabetes mellitus; IHD: Ischaemic heart disease; NHS: National Health Service.