How to recognise and approach diabetic remission
Good glycemic control soon after diagnosis reverses glucose toxicity and many newly-diagnosed diabetic cats can have their insulin dose gradually reduced and many can have their insulin completely withdrawn. It is suggested that insulin not be withdrawn completely for at least two weeks after starting insulin therapy to ensure adequate time for beta cells to recover from glucose toxicity.
Insulin dose can be reduced when indicated by low blood glucose parameters listed above. If pre-insulin glucose is below 10mmol/L and insulin dose has been reduced to 1U, insulin should be withheld and blood glucose measured for 12hrs (if the pre-insulin glucose is below 10mmol/L and insulin dose greater than 1U, insulin dose should be reduced to 1U rather than withheld and pre-insulin glucose measured again in 3-7 days). In most cases, if when insulin is withheld the blood glucose concentration
- rises rapidly or significantly over 10mmol/L cats should be discharged on 1U twice daily
- rises slowly towards or just above 10mmol/L, then cats should be discharged on 1U once daily
- remains below 10mmol/L for 12hrs with no insulin, they can be assumed to be non-insulin dependant and cats should be discharged without insulin with their blood glucose monitored every 2-3 days for several weeks. Confirmed non-insulin dependant diabetic cats should have their blood glucose checked weekly for 3 months and then monthly forever.
Some cats may have a pre-insulin glucose concentration below 10mmol/L within 2 weeks, but insulin therapy should be maintained for at least 2 weeks to give beta cells adequate time to recover from glucose toxicity. Use 1U BID or SID until insulin is withdrawn.
What to do with a diabetic cat in remission
Once remission has occurred, it is vital that blood glucose concentration be measured regularly (initially weekly then monthly) to quickly diagnose a relapse. To facilitate the cat remaining in diabetic remission, it is recommended that a low carbohydrate diet is fed, physical activity is increased, calories are restricted to avoid obesity, and that diabetogenic drugs are contraindicated unless a life threatening situation arises.
How to increase the chance of remission occurring
Our study in diabetic cats (Marshall et al, awaiting publication) found better glycaemic control and higher remission rates when newly diagnosed diabetic cats were treated with glargine compared to lente or PZI insulins. This study also showed that, regardless of insulin type, good glycaemic control soon after diagnosis (within 3 weeks) increases the chance of achieving remission.
For reasons that are presently unknown, glargine treated cats appear to tolerate slight overdosing with insulin very well. For this reason, it is suggested that for the first 4-6 weeks of therapy, insulin be slightly overdosed and cats monitored carefully. Slightly overdosing with glargine increases the risk of hypoglycemia but usually results in achieving early good glycemic control which reverses glucose toxicity and results in a non-insulin dependant state. The benefits of remission far outweighs the risks of hypoglycaemia.
To maximise glycaemic control and hence the chance of remission
- select glargine as initial insulin
- administer glargine TWICE daily rather than once daily
- slightly overdose with insulin for the first 4-6 weeks
- use a low carbohydrate diet
- restrict calories if overweight and encourage physical activity