A computerized scoring system to improve assessment of heparin-induced thrombocytopenia risk

Improving Judicious Use of Heparin-Induced Thrombocytopenia Testing Through Electronic Health Record-Based Intervention

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an immune-mediated drug reaction that can cause thromboembolism in the setting of thrombocytopenia. An enzyme-linked immunosorbent assay (ELISA)-based assay to screen for HIT antibodies (HAb) is available but has relatively low specificity and a correspondingly high false positive rate. The 4Ts score has been validated to determine the pretest probability of HIT. The authors hypothesized that an electronic health record (EHR)-based clinical decision support (CDS) tool incorporating the 4Ts score would reduce the volume of HAb orders.

METHODS

After implementing a CDS tool into the EHR, the researchers retrospectively evaluated the impact from November 2019 to October 2021, compared to a preintervention period (January to October 2019). The primary outcome was average tests per month. Secondary outcomes included rates of tests ordered per total inpatient encounters and proportion of HAb sent despite low 4Ts score in the postintervention study period.

RESULTS

Of 1,833 HAb sent during the study period, 1,217 occurred in the postintervention period. In the postintervention period compared with the preintervention period, the average orders per month was 50.5 (standard deviation [SD] 9.7) vs. 61.6 (SD 7.2) (p = 0.003), and the order incidence rate was 8.0 per 1,000 patient encounters postintervention vs. 9.2 per 1,000 patient encounters preintervention (rate ratio [RR] 0.87, 95% confidence interval [CI] 0.79-0.96, p = 0.002). Postintervention, 252 (20.7%) had a 4Ts score calculated as low probability, 759 (62.4%) as intermediate probability, and 131 (10.8%) as high probability, and 75 had no associated 4Ts score.

CONCLUSION

Implementation of a simple CDS tool reduced the rate of HAb orders, reducing unnecessary HAb testing.

Clinical decision support to reduce unnecessary diagnostic testing for heparin-induced thrombocytopenia

Appropriate evaluation of heparin-induced thrombocytopenia (HIT) is imperative because of the potentially life-threatening complications. However, overtesting and overdiagnosis of HIT are common. Our goal was to evaluate the impact of clinical decision support (CDS) based on the HIT computerized-risk (HIT-CR) score, designed to reduce unnecessary diagnostic testing. This retrospective observational study evaluated CDS that presented a platelet count versus time graph and 4Ts score calculator to clinicians who initiated a HIT immunoassay order in patients with predicted low risk (HIT-CR score 0-2). The primary outcome was the proportion of immunoassay orders initiated but cancelled after firing of the CDS advisory. Chart reviews were conducted to assess anticoagulation usage, 4Ts scores and the proportion of patients who had HIT. In a 20-week period, 319 CDS advisories were presented to users who initiated potentially unnecessary HIT diagnostic testing. The diagnostic test order was discontinued in 80 (25%) patients. Heparin products were continued in 139 (44%) patients, and alternative anticoagulation was not given to 264 (83%). The negative predictive value of the advisory was 98.8% (95% CI: 97.2-99.5). HIT-CR score-based CDS can reduce unnecessary diagnostic testing for HIT in patients with a low pretest probability of HIT.

Next-generation diagnostic instruments in haematology

Gallo et al. assessed the impact of implementing a clinical decision support tool in a multi-hospital setting. This is one of three important points to unlock the capabilities of the next-generation of diagnostic instruments: (a) integrating diagnostic information from various sources, (b) ensuring accurate development and validation in well-designed clinical studies and (c) seamlessly integrating them into clinical practice. Commentary on: Gallo et al. Clinical decision support to reduce unnecessary diagnostic testing for heparin-induced thrombocytopenia. Br J Haematol 2023;202:1011-1017.

Tackling alert fatigue with a semi-automated clinical decision support system: quantitative evaluation and end-user survey

STUDY AIMS

Clinical decision support systems (CDSS) embedded in hospital electronic health records efficiently reduce medication errors, but there is a risk of low physician adherence due to alert fatigue. At the Cantonal Hospital Aarau, a CDSS is being developed that allows the highly accurate detection and correction of medication errors. The semi-automated CDSS sends its alerts either directly to the physician or to a clinical pharmacist for review first. Our aim was to evaluate the performance of the recently implemented CDSS in terms of acceptance rate and alert burden, as well as physicians' satisfaction with the CDSS.

METHODS

All alerts generated by the clinical decision support systems between January and December 2021 were included in a retrospective quantitative evaluation. A team of clinical pharmacists performed a follow-up to determine whether the recommendation made by the CDSS was implemented by the physician. The acceptance rate was calculated including all alerts for which it was possible to determine an outcome. A web-based survey was conducted amongst physicians to assess their attitude towards the CDSS. The survey questions included overall satisfaction, helpfulness of individual algorithms, and perceived alert burden.

RESULTS

In 2021, a total of 10,556 alerts were generated, of which 619 triggered a direct notification to the physician and 2,231 notifications were send to the physician after evaluation by a clinical pharmacist. The acceptance rates were 89.8% and 68.4%, respectively, which translates as an overall acceptance rate of 72.4%. On average, clinical pharmacists received 17.2 alerts per day, while all of the hospital physicians together received 7.8 notifications per day. In the survey, 94.5% of physicians reported being satisfied or very satisfied with the CDSS. Algorithms addressing potential medication errors concerning anticoagulants received the highest usefulness ratings.

CONCLUSION

The development of this semi-automated clinical decision support system with context-based algorithms resulted in alerts with a high acceptance rate. Involving clinical pharmacists proved a promising approach to limit the alert burden of physicians and thus tackle alert fatigue. The CDSS is well accepted by our physicians.

Computerised risk scores to guide recognition and diagnosis in patients with possible heparin-induced thrombocytopenia

The heparin-induced thrombocytopenia computerised risk (HIT-CR) score is designed to aid in the diagnosis of HIT. We sought to evaluate its potential clinical utility. In this retrospective cohort study, we collected HIT-CR scores on all inpatients receiving heparin over a 4-month period and performed chart reviews on the subset who independently underwent clinical diagnostic testing for HIT to identify patients with HIT. In all, 34 342 patients received heparin, 1744 had high-risk HIT-CR scores of ≥3 and 220 had the maximal risk score of 4. Only 6% of high-risk and 10% of maximal-risk patients underwent testing for HIT. Conversely, among all 317 patients who underwent independent testing for HIT, 67% had low-risk HIT-CR scores (<3). Among patients independently tested, the positive predictive value (PPV) was 6·6% [95% confidence interval (CI) 4·9-8·8%] and the negative predictive value (NPV) was 99·5% (95% CI 97·1-99·9%) at a HIT-CR score cut-off of 3, and the PPV was 22·7% (95% CI 12·7-37·4%) and NPV was 99·0% (95% CI 97·6-99·6%) at a cut-off of 4. This study suggests clinicians fail to test most high-risk patients and unnecessarily test many low-risk patients for HIT. A reasonable approach to clinical application of HIT-CR scores would be recommending no testing for patients with a score of <3 and recommend testing for patients with a score of 4.