CME
Physicians: maximum of 1.00 AMA PRA Category 1 Credit
Released: June 11, 2025
Expiration: June 10, 2026
Patient Case 2: Navigating Drug Interactions and Comorbidities
Next, let us go through another case, which will highlight some additional features of HIV-ASSIST.
Imagine that the 52-year-old patient from the first case also had hyperlipidemia and pulmonary tuberculosis.
In this instance, the individual was already receiving atorvastatin for hyperlipidemia and is also receiving rifampicin, isoniazid, pyrazinamide, and ethambutol for tuberculosis. The care team is ready to start ARVs for HIV, but in this case, HIV-1 RNA, CD4+ cell counts, and other information is unavailable. This reflects a common scenario in many settings.
HIV-ASSIST Input: Comorbidities and Comedications
Let us see how this particular set of inputs affects the HIV-ASSIST output.
First, indicate that the HIV-1 RNA and the CD4+ cell count are unknown. The HIV-ASSIST tool will then apply different algorithms to account for this scenario.1
Next, you can add hyperlipidemia as a comorbidity. Then, adding in the various comedications will instruct the system to pull information on drug–drug interactions from the University of Liverpool HIV drug interaction database, which will be considered in the output.1,5
HIV-ASSIST Output: Potential Regimens With Color-Coding and Weighted Scores
That brings us to the output for this case scenario. Here you see that although this patient is also treatment naive, there are no regimens that are coded as dark green. This is because of the various trade-offs involving drug interactions and comorbidity considerations.1
The key difference between this scenario and the first one is that the weighted scores for each regimen are now higher because they reflect additional considerations. In this case, TLD may be the best choice for this patient based on particular characteristics.1
A factor behind the worse weighted score for TLD is the dosing frequency of twice daily. Although the drug is expected to be efficacious, the twice-daily dosing frequency does carry with it a risk of reduced adherence. This is reflected as an increase in the final weighted score.1
HIV-ASSIST Output: Potential Regimens With Color-Coding and Weighted Scores
Clicking on “TLD” and navigating to the “Rationale” tab will pull up a step-by-step explanation of how HIV-ASSIST derived this score.1
HIV-ASSIST Provides Transparent Explanations of All Rules Leading Final Score and Ranking (Rationale Tab)
The goal of the rationale tab is to aid HCPs in identifying the considerations that might go into making their final decision.
In some instances, HCPs may disagree with the specific weight that HIV-ASSIST has applied to different factors. HIV-ASSIST’s algorithms are based on the findings of a scientific advisory panel that put great effort into calibrating these weights, but every individual circumstance is a bit different and deserves to be considered as such.1
In this case scenario, TLD had a very favorable base score of 1, which would normally have been dark green. Yet the DTG dosing had to be increased to twice daily because of the drug interaction with rifampin. As a result, the score reflects a penalty because of this drug interaction and the increased pill burden.1
HIV-ASSIST Provides Dosing Information in the Dosing Tab after Clicking on the Regimen
This information is also available by clicking on the “dosing information” tab. One of the benefits of HIV-ASSIST is that it has already integrated all of those drug interactions and dosing changes into its algorithms.1
In this instance, clicking on “dosing information” will show that the patient should still take TLD once daily, with an additional DTG dose in the evening, ultimately making this a twice-daily regimen.1
The “dosing information” tab also summarizes some of the food effects, administration, drug interactions, and additional considerations such as common adverse effects. All of this information is simply laid out to HCPs for their consideration.1
HIV-ASSIST Output: Dosing Information by Clicking on the Regimen
This case scenario demonstrates that the HIV-ASSIST dosing recommendations are consistent with current WHO guidelines, which indicate that when rifampin is used with DTG, the dosage must be raised to 50 mg twice daily.1,3
This is another example of how HIV-ASSIST can aid HCPs in synthesizing the large volume of information that is embedded inside of the numerous HIV guidelines.1
HIV-ASSIST: Additional Information Tab Provides Information on Mutations, Comorbidities, Drug Interactions
Even more detailed information regarding mutation penalties, drug interactions, and the impact of comorbidities can be accessed by clicking “Additional information” on the main output screen.1
HIV-ASSIST: Additional Information Tab Explains Drug Interactions
Clicking on “Comedications” will show a list of the possible comedication interactions. Clicking on a particular comedication such as atorvastatin will bring up an evaluation for interactions with every listed ARV agent.1
If there are no interactions with the patient’s comedications, the ARV shows up as green. Clicking on a specific ARV will show additional notes related to that particular interaction. For example, in this case scenario, atorvastatin was one of the drugs used by the patient. Clicking on “FTC” shows that there is no interaction between emtricitabine and atorvastatin.1
HIV-ASSIST: Additional Information Tab Explains Drug Interactions and Their Impact on Scores
On the other hand, if one navigated to rifampin and clicked on DTG, all information from Liverpool's interaction database becomes available.1
This page includes a detailed explanation of the interaction between rifampin and DTG and the available pharmacokinetic data. This summary indicates the way in which coadministration of rifampin and DTG reduces DTG, helping HCPs further understand the rationale behind recommended ART regimens.1
HIV-ASSIST: Additional Information Tab Explains Scoring for Individual ARVs Based on Comorbidities
HIV-ASSIST also evaluates the impact of different comorbidities when calculating scores, such as hyperlipidemia or coronary artery disease.1
For this case scenario, hyperlipidemia leads to a slight prioritization of TDF over some other drugs. That is, clicking on TDF reveals that it was assigned a penalty, which is interpreted as a prioritization.1
HIV-ASSIST applied this prioritization based on the DHHS guidance that TDF is associated with lower lipid levels than other NRTIs, such as abacavir or tenofovir alafenamide. The guidelines state that TDF lowers lipids and that switching from TDF to tenofovir alafenamide may be associated with increased lipid profiles1,2
Altogether, this highlights further how subtle nuances and details embedded in HIV treatment guidelines are comprehensively incorporated into the HIV-ASSIST algorithms.
HIV-ASSIST: Additional Information Tab Explains Scoring for Individual ARVs Based on Comorbidities
Similar to how the “additional information” tab can be used to learn how comedications interact with specific ARVs, this feature can also show HCPs how comorbidities affect certain drugs.1
HIV-ASSIST: Additional Information Tab Explains Scoring for Individual ARVs Based on Comorbidities
For example, PIs were not considered for this treatment-naive patient, but they might be considered for others in different circumstances. In those situations, HCPs could use this tab to see that, in the presence of hyperlipidemia PIs are given a slight penalty because all ritonavir or cobicistat boosted PIs can increase triglyceride or LDL levels.1
This is another way that HIV-ASSIST applies existing information and guideline recommendations towards determining the optimal ART regimen for a specific patient.1
HIV-ASSIST: Additional Information Tab Also Provides Mutation and Resistance Information if Present
Lastly, neither of these case scenarios described patients with drug resistance. But if there is drug resistance, HCPs can learn how it affected the output by clicking on the “mutation penalties” box from the main output screen.1
HIV-ASSIST Helps HCPs …
Overall, HIV-ASSIST can help HCPs select individualized ARV regimens through a free online guideline-based decision support tool.
HIV-ASSIST helps HCPs in their routine practice by delivering point-of-care, evidence-based clinical decision support. The HIV-ASSIST algorithm weighs the evidence related to achieving virologic suppression, incorporates other factors related to tolerability and safety, and weighs patient preferences that might affect treatment adherence or long-term ability to take the ARV regimen.
The goal is for HIV-ASSIST is not to replace HCPs but to help inform decisions. HIV-ASSIST allows HCPs to take into consideration individual circumstances, including resistance mutations, comorbidities, comedications, and other factors to optimize ART regimens for each individual.
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