To analyse predictors of hypoglycemia unawareness (HU) and improvement in Clarke score in clinical practice.We retrospectively identified patients with type 1 diabetes (T1D) at an academic T1D clinic who completed HU surveys 6-12 months apart. HU (Clarke score ≥4) and improvement in Clarke score (decrease by ≥1 point or more clinically relevant ≥2 point) were assessed in univariable relationships and using multivariable logistic regression.Of the 300 participants, median diabetes duration was 19 years, 47 had HU at baseline, and 91 had an improvement by 1 point while 21 had an improvement by 2 points. Patients with baseline Clarke score ≥4 who had ≥1 or ≥2 point improvement had lower filtration rate (eGFR) than those who did not. After adjustment for other variables, gender (male OR 0.33, 95% CI 0.15, 0.74), log diabetes duration (OR 6.40, 95% CI 2.84, 14.5), and eGFR60 ml/min/1.73 mDiabetes duration, gender, and eGFR were independent predictors of HU. Improvement in Clarke score is possible in patients with long-standing T1D, underscoring the need for additional study.