Think-HF: Development, feasibility, and usability of an electronic health record integrated tool for identifying missed diagnoses of heart failure in primary care

BackgroundMany patients with heart failure (HF) remain undiagnosed until acute hospital admission for decompensation. Think-HF is a clinical decision support tool (CDST) designed to identify possible undiagnosed HF in primary care and trigger timely, guideline recommended assessment. MethodsThink-HF was developed through epidemiological evidence and codesign. Integrated within SystmOne, it analyses routine primary care data (codes, medications, test results, free text) to detect missed or emerging HF signals. When a record is opened, if a patient has [≥] two comorbidity indicators plus an HF-suggestive symptom, an alert is triggered and a structured template opens with one-click options for natriuretic peptide (NP) testing, echocardiography, specialist referral and coding. Additional algorithms identify unresolved investigations, coding inconsistencies and medication-based signals, generating a marker on the patients record. A mixed-methods feasibility study across six primary care practices assessed reach, usability, acceptability, and early implementation signals, using the RE-AIM framework. ResultsSix socioeconomically and ethnically diverse general practices participated (63 GPs; 78,640 patients [47.5% women, 59.4% White, 17.8% South Asian, 8.5% Black, 3% Chinese and 2.8% mixed ethnicities]). At baseline, 876 patients (1.1%) met the main alert criteria and 2,805 (3.6%) met additional algorithm criteria. Of 801 patients on the HF register, 665 (83%) lacked a refined HF left ventricular phenotype code. During four months of testing, Think-HF generated 299 clinically relevant main trigger alerts (75% during consultations). Early improvements included (i) 31 new HF diagnoses (+4.2%), with higher gains (+10%) in practices with lower baseline prevalence; (ii) a 14% increase in refined HF phenotype coding; (iii) fewer raised NT-proBNP results without follow-up (-7%); and (iv) fewer patients prescribed loop diuretics without NP testing (-14%, up to -45% in one practice with pharmacist-supported review). Clinicians reported improved awareness, more systematic assessment, and better follow-up of missed investigations or coding anomalies. Identified gaps aligned with patient-reported delays and misattributed symptoms. ConclusionsThink-HF is feasible, acceptable and well aligned with routine primary care workflows. Early gains in diagnostic processes and coding accuracy highlight its potential to improve patient care. Team-based implementation will be essential for scale-up. Larger evaluation is required to assess clinical impact.