Introduction In Sweden, quality indicators in health care have been the basis for developing National Quality Registers. The Swedish National Diabetes Register (NDR) – one of the largest diabetes registers globally – was introduced in primary health care (PHC) in the county of Östergötland by an implementation project, 2002–2005.

Aim The aim of the present paper was to investigate, by using the results of the NDR, whether the registration led to sustained outcomes of medical results of diabetes care in PHC in the county during the period 2005–2009.

Method HbA1c, blood pressure (BP), albuminuria and low-density lipoprotein-cholesterol were registered online in the NDR. In 2005 and 2006, goal achievement for HbA1c was measured and compared between PHC centres (PHCC) within the county. In 2007, achievements to national goals were compared between the PHCCs within the county and with those Swedish counties that had attained a sufficiently high registration rate. In 2008 and 2009, the average county results were compared with the corresponding national average measurements for all 21 Swedish counties combined.

Result In 2005, a clear improvement trend for HbA1c and BP was shown within the county. In 2007–2009, goal achievements in the county studied were slightly better than the other counties measured and the country as a whole in almost every comparison.

Discussion The present study has shown association between medical results and registration in the NDR. As the project was primarily a quality improvement work, the results have continuously influenced the development of diabetes care. Both the health professions and the county council now have – in the NDR – an effective and rapid method for evaluation and follow-up of diabetes care. The systematic documentation, followed by comparisons and analyses, create ideas for care improvements.