HIPAA-Compliant Patient Risk Stratification Algorithm

Design a PostgreSQL stored procedure that anonymizes patient data while creating a predictive risk score for chronic disease management. The procedure must implement k-anonymity principles, use advanced statistical aggregation techniques, and generate a risk classification without exposing individual patient identifiers. Include error handling for data integrity and implement row-level security to ensure HIPAA compliance. The output should provide a risk score between 0-100 with associated confidence intervals.