Vaccines for the prevention of seasonal influenza in patients with diabetes: systematic review and meta-analysis

Table 2 Pooled crude and adjusted odd ratios of influenza vaccine effectiveness (per outcome) during influenza-season and off-season in vaccinated vs. unvaccinated diabetic patients

Age-group (years)	Outcome/Design		No of studies included	Crude OR (95% CI)	I ²	No of studies included	Adjusted OR (95% CI)	I ²	No of studies included	Off-season adjusted OR (95% CI)	I ²
0–17	No studies		0	–	–	0	–	–	0	–	–
18–64	All-cause mortality
		Case–control studies	1	0.46 (0.11–1.89)	NA¹	1	0.76 (0.07–8.06)	NA¹	0	–	NA¹
	All-cause hospitalization
		Case–control studies	2	0.32 (0.19–0.54)	0%	3	0.42 (0.19–0.94)	77%	1	0.73 (0.65–0.83)	NA¹
	Influenza/pneumonia hospitalization
		Case–control studies	0	–	–	1	0.57 (0.46–0.72)	NA¹	1	0.88 (0.68–1.14)	NA¹
	Influenza-like illness
		Cohort studies	1	0.76 (0.50–1.15)	NA¹	0	–	–	0	–	–
		Case–control studies	0	–	–	1	0.99 (0.97–1.01)	NA¹	1	1.00 (0.90–1.12)	NA¹
≥65	All-cause mortality
		Cohort studies	3	0.54 (0.37–0.79)	90%	2	0.62 (0.57–0.68)	0%	1	0.70 (0.37–1.31)	NA¹
		Case–control studies	2	0.39 (0.35–0.43)	0%	2	0.44 (0.36–0.53)	0%	0	–	–
	All-cause hospitalization
		Cohort studies	1	0.83 (0.72–0.95)	NA¹	0	–	–	1	0.91 (0.71–1.17)	NA¹
		Case–control studies	2	0.89 (0.81–0.98)	0%	3	0.77 (0.60–0.99)	94%	1	0.66 (0.59–0.74)	NA¹
	Influenza/pneumonia hospitalization
		Case–control studies	1	0.20 (0.07–0.61)	NA¹	1	0.55 (0.47–0.66)	NA¹	1	0.48 (0.32–0.70)	NA¹
	Influenza-like illness
		Case–control studies	0	–	–	1	0.87 (0.84–0.90)	NA¹	1	0.82 (0.70–0.96)	NA¹
Not reported	Influenza/pneumonia hospitalization
		Cohort studies	1	1.75 (0.10–32.68)	NA¹	0	–	–	0	–	–
	Influenza-like illness
		Cohort studies	1	0.34 (0.02–5.85)	NA¹	0	–	–	0	–	–

ISSN: 1741-7015