Table 3.

Limitations associated with study outcomes in 16 studies reviewed

Issue	Limitation
Design	Not randomised [24,27]
	No control group [28]
	Short duration of the intervention [[15], 1623]
Sample	Sample not representative [22,23]
	Small sample size [28]
	Sampling population restricted to patients who accessed hospital web page [30]
Intervention effect	Unable to determine intervention component contributing to the observed change [23,29]
	Unmeasured variable contributing to observed change [28]
	Possibility of increased attention to management contributing to observed change [19,20]
	Mean baseline HbA1c close to 7% [17,20,25]
	Concomitant exposure to another intervention [27]
Participant dropout	Non-random participant dropout [19]
	Complete data not available for all participants [29]