Polonsky et al.(1) reporting that self-monitoring of blood glucose (SMBG) improves glycemic control in noninsulin-treated type 2 diabetes. In the UK, SMBG is recommended for insulin-treated diabetes (2), and controversy exists in relation to treatment with lifestyle advice or oral hypoglycemic agents (OHAs). A Cochrane review concluded that there is insufficient evidence to support the use of SMBG in noninsulintreated type 2 diabetes (3). Furthermore, a health technology assessment review suggests that SMBG has limited clinical effectiveness in improving glycemic control in noninsulin-treated type 2 diabetes (4). In view of the widespread use of SMBG, cost implications, and the fact that UK management algorithms are based on HbA1c targets (2), clarity is required on the role of SMBG.

We used the SAIL (Secure Anonymised Information Linkage) databank (5) to examine glucose strip prescribing in relation to HbA1c in groups treated with diet, OHAs, and insulin. SAIL contains patient data from 35 primary care systems for the Swansea area (n 5 250,086). We