I, 68 male, am diabetic since 25 years. I used to maintain stable hba1c 6.3 so far, with one glitaris 7.5 mg and one glycomet 500 mg after dinner. Serum creatinine also remained stable at 1.15. However, hba1c increased to 6.6 in last one year with the same dose of medicine and no change in life style (i never miss my exercise schedule). Along with this increased blood sugar, serum creatinine also jumped from 1.15 to 1.24. As it is long-standing diabetes, I am under consultation with nephrologist. He has added sobisis (half tablet twice in a day) and homochek (one daily). This is in addition to my anti-diabetic drugs. I understand that hba1c, serum creatinine and egfr co-vary and are correlated statistically. It means if I bring down my sugar level with extra dose of medicine (may be one tablet in the morning) it could improve my creatinine level. However, my nephrologist didn?t agree with this. He told me that hba1c of 6.6 is no problem considering my age. He added that tight control of sugar can adversely affect brain and I should continue with my set prescription. My concern is what hba1c value is safe for my kidney? I scanned number of papers and struck two values of hba1c upper limit 6.5 and 7. According to this, as long as hba1c is within 7 one should not worry. Nevertheless, because the increased hba1c seems to be impacting my creatinine, I would like to bring it down at least to less than 6.5 with extra anti-diabetic dose. I don?t think it is a tight control of sugar. Please advise.