Recommendations for the use of antiretroviral therapy in adults living with human immunodeficiency virus in Singapore

ABSTRACT

Since the advent of combination antiretroviral therapy (ART), the mortality attributable to human immunodeficiency virus (HIV) infection has decreased by 80%. Newer antiretroviral agents are highly efficacious, have minimal side effects as compared to older drugs, and can be formulated as combination tablets to reduce patients' pill burden. Despite these advances, 680,000 people worldwide died of acquired immunodeficiency syndrome-related illnesses in 2020. The National ART and Monitoring Recommendations by the National HIV Programme have been created to guide physicians on the prescribing of ART based on the patients' needs. These recommendations are based on international guidelines and tailored to the local context and unique domestic considerations. We hoped that with the publication of these recommendations, the care of people living with HIV can be enhanced, bringing us closer to ending HIV in our lifetime.

An overview of multimorbidity and polypharmacy in older people living with HIV

The availability of effective antiretroviral therapy (ART) has revolutionized the care of people living with HIV (PLHIV). As a result, PLHIV now have a life expectancy comparable with that of the general population. PLHIV are increasingly confronted with age-related comorbidities and geriatric syndromes, including frailty and polypharmacy, which occur at a higher prevalence and set in at an earlier age compared with their uninfected counterparts. The underlying pathophysiology for multimorbidity and polypharmacy are multifactorial, multidimensional and complex. Therefore, regular review and optimization of risk factors to maintain physical function, social and psychological health is of utmost importance. With an ever-growing population of older PLHIV, there is a pressing need to provide holistic care to address these emerging issues. Accelerated aging observed in PLHIV suggests that early involvement of a multidisciplinary team, including geriatricians, and implementation of integrated models of care can potentially improve the care of older PLHIV, who are at increased risk of frailty and complex multimorbidity. This article reviews the current global situation, discusses the challenges involved and suggests approaches to deliver comprehensive care for older PLHIV. Geriatr Gerontol Int 2024; 24: 49-59.

Quantification of Fosfomycin in Combination with Nine Antibiotics in Human Plasma and Cation-Adjusted Mueller-Hinton II Broth via LCMS

Fosfomycin-based combination therapy has emerged as an attractive option in our armamentarium due to its synergistic activity against carbapenem-resistant Gram-negative bacteria (CRGNB). The ability to simultaneously measure fosfomycin and other antibiotic drug levels will support in vitro and clinical investigations to develop rational antibiotic combination dosing regimens against CRGNB infections. We developed an analytical assay to measure fosfomycin with nine important antibiotics in human plasma and cation-adjusted Mueller–Hinton II broth (CAMHB). We employed a liquid-chromatography tandem mass spectrometry method and validated the method based on accuracy, precision, matrix effect, limit-of-detection, limit-of-quantification, specificity, carryover, and short-term and long-term stability on U.S. Food & Drug Administration (FDA) guidelines. Assay feasibility was assessed in a pilot clinical study in four patients on antibiotic combination therapy. Simultaneous quantification of fosfomycin, levofloxacin, meropenem, doripenem, aztreonam, piperacillin/tazobactam, ceftolozane/tazobactam, ceftazidime/avibactam, cefepime, and tigecycline in plasma and CAMHB were achieved within 4.5 min. Precision, accuracy, specificity, and carryover were within FDA guidelines. Fosfomycin combined with any of the nine antibiotics were stable in plasma and CAMHB up to 4 weeks at −80 °C. The assay identified and quantified the respective antibiotics administered in the four subjects. Our assay can be a valuable tool for in vitro and clinical applications.

34. Stemming the Rise in Antibiotic Prescription for Community Acquired Respiratory Infections (ARI) During COVID-19 Pandemic in Singapore General Hospital (SGH)

Background

In early months of COVID-19 pandemic, SGH recorded a year-on-year increase in antibiotic (ABx) use for community acquired acute respiratory infection (CA ARI) from Feb-Apr 2019 (48.7 defined daily doses (DDD)/100 bed-days) to 2020 (50.8 DDD/100 bed-days). To address concerns of misuse, the antibiotic stewardship unit (ASU) expanded prospective audit feedback (PAF) to CA ARI patients admitted to ARI wards, with low procalcitonin (PCT). PAF was conducted on day 2-3 of ABx, on weekdays. Doctors received feedback to stop/modify when ABx was deemed inappropriate. Here, we describe the impact of ASU’s adaptive approach to curb rising ABx use in patients admitted for ARI during COVID-19 pandemic.

Methods

A Pre- & Post-intervention study was conducted. All patients started on ABx (ceftriaxone/co-amoxiclav/piptazo/carbapenems/levofloxacin) for CA ARI & PCT < 0.5µg/L were analysed. Those who died ≤48h of admission; admitted to intensive care; required ABx escalation; >1 infective sites; complex lung infection were excluded. Primary objective was to compare the proportion of ABx stopped ≤4 days (time to final infection diagnosis) Pre (22/3-18/4/20) & Post (21/4-13/7/20).

Results

184 (Pre) & 528 (Post) ABx courses were analysed. ASU audited 51 (Pre) & 380 (Post) courses with the rest discontinued/discharged before review. Patients were largely similar in both periods; a third had low likelihood of bacterial infection (C reactive protein < 30mg/L). In Post, 73 feedback was given to stop ABx (often because symptoms suggested viral/fluid overload) & 18 to switch to oral ABx. 82 (90%) feedback was accepted. No ABx was restarted ≤48h or deaths ≤30 days due to ARI. 1 patient had C. difficile diarrhoea a day after ABx cessation as per ASU feedback.

Proportion of all ABx stopped ≤4 days was higher in Post than Pre [27/184 (15%) vs 152/528 (29%), p< 0.01]. Median duration of therapy of IV ABx was reduced (6.5 vs 3 days, p< 0.01), with corresponding shorter median length of stay (10.5 vs 6 days, p< 0.01).

Conclusion

PAF directly and indirectly reduced ABx duration in patients treated for CA ARI as prescribers become more conscious about stopping ABx when investigations show low likelihood of bacterial infection. ASU must remain agile during pandemics to detect emerging problems and adapt processes to counter early.

Disclosures

All Authors: No reported disclosures

141. Effectiveness of a Multipronged Approach to Improve Prophylactic Antibiotic Prescribing in Patients Undergoing Trans-Arterial Chemoembolization

Background

In our institution, the significant use of broad-spectrum antibiotics for antibiotic prophylaxis (AP) in trans-arterial chemoembolization (TACE) was operator dependent and not evidence based. Hence, an AP guideline was developed with the Department of Vascular and Interventional Radiology and launched in May 2019, following department roadshows and creation of user-friendly electronic AP order sets. We analyzed the effectiveness and outcomes of our multipronged approach towards improving the standardization of AP prescribing.

Methods

This was a retrospective study of TACE procedures from November 2018 to March 2020, pre and post guideline implementation (Figure 1). Single IV cefazolin 2g dose (or IV clindamycin 600mg in the setting of β-lactam allergy) before TACE in patients with an uncompromised sphincter of Oddi was recommended. Patients with active infections prior to TACE were excluded. AP was deemed inappropriate if it deviated from guidelines (antibiotic choice and/or duration). Primary outcome was AP appropriateness and 30-day TACE related infections.

Figure 1. Timeline of our multipronged approach

Results

Seventy patients were included. There were no differences in baseline demographics pre and post implementation (Table 1). Following guideline implementation, there was a significant improvement in AP used for TACE. AP appropriateness pre-implementation and post-implementation was 14/31 (45.2%) and 37/39 (94.9%) respectively (p< 0.001). Guideline compliant antibiotics were selected more frequently (14 [45.2%] vs 38 [97.4%], p< 0.001), and more patients received single dose AP (22 [71.0%] vs 38 [97.4%], p=0.004). Of the 18 patients who did not receive guideline recommended AP, 16 (88.9%) received IV ceftriaxone and metronidazole, 1 (5.6%) IV amoxicillin/clavulanic acid, and 1 (5.6%) IV ciprofloxacin. Ten patients received a prolonged course of AP with a median duration of 6 days (IQR 4.3, 6.5). There were no significant differences in 30-day TACE related infections (1 [3.2%] vs 2 [5.1%], p=1.000) and 30-day mortality (1 [3.2%] vs 1 [2.6%], p=1.000). No patient had surgical site skin infection.

Conclusion

Our multipronged approach improved AP prescribing in patients undergoing TACE. Single dose IV cefazolin prophylaxis for TACE did not compromise safety outcomes in the post implementation review.

Disclosures

All Authors: No reported disclosures

2107. Azole Therapeutic Drug Monitoring (TDM) in a Multiracial Cohort with Varied Pharmacogenetics

Background

Voriconazole (VOR) and posaconazole (POS) exhibit wide pharmacokinetic variability. Various factors including race and genetic polymorphisms are at play and this may affect treatment response. We aim to evaluate the utility of VOR/POS TDM among Southeast Asians that are predominantly intermediate/poor VOR metabolizers.

Methods

All adults with VOR/POS TDM performed at our institution from 2015 to 2018 were included. We determined proportion of patients and doses required to achieve TDM targets [(2 – 5.5 mg/L (VOR) or ≥ 0.7 and ≥ 1.0 mg/L (POS prophylaxis and treatment respectively)], and correlate levels with treatment efficacy and safety.

Results

VOR/POS TDM was performed mostly among patients with hematological malignancy or solid-organ transplant (146/174, 83.9%). Less than half (32/70, 45.7%) of patients on VOR achieved target—18 (25.7%) were < 2 mg/L while 20 (28.5%) had levels > 5.5 mg/L. Doses required to achieve TDM target ranged from 1.9–11.4 mg/kg/day. Drug interactions, critically ill state and change in drug formulation were major causes of intra-patient variability. One-fifth (n = 14) experienced transaminitis; corresponding VOR trough levels were 0.5–> 7.5 mg/L. Neurotoxicity was also seen in 3 (4.3%) patients—all 3 had VOR trough ≥ 6.7 mg/L and saw symptom resolution upon dose reduction. There appears to be no association between the achievement of TDM targets and response rates. Majority (81/104, 77.9%) of patients on POS achieved TDM targets. Patients prescribed POS tablet were significantly more likely to attain targets compared with suspension 600 mg/day [19/26 (73.0%) vs. 27/62 (43.5%), P < 0.05] and 800 mg/day [17/26 (65.3%) vs. 4/16 (25.0%), P < 0.05)]. Of 23 with sub-therapeutic levels, 19 (82.6%) responded to dose increase and/or change in acid-reducing agents. Breakthrough infection occurred despite troughs ≥ 0.7 mg/L [5/42 (11.9%) vs. 2/40 (5.0%) when < 0.7 mg/L (P = 0.3)]. Treatment failure was observed in 2 patients (troughs > 1.0 mg/L).

Conclusion

VOR/POS TDM should be implemented in Southeast Asians due to significant unpredictability in dose exposure and potential to avoid need for switch to alternative anti-fungals due to intolerability. Higher POS trough cutoff may be required for effective anti-fungal prophylaxis.

Disclosures

All authors: No reported disclosures.

Prospective audit and feedback in antimicrobial stewardship: is there value in early reviewing within 48 h of antibiotic prescription?

Antimicrobial stewardship programme (ASP) methodologies are not well defined, with most preferring to wait ≥72-96 h following antibiotic prescription before reviewing patients. However, we hypothesise that early ASP reviews and interventions are beneficial and do not adversely impact patient safety. This study aimed to evaluate the impact of early ASP interventions within 48 h of antibiotic prescription on patient outcomes and safety. A prospective review of ASP interventions made within 48 h of antibiotic prescription in Singapore General Hospital (SGH) from January to December 2012 was conducted. Patient demographics and outcomes were extracted from the database maintained by the ASP team. For culture-directed treatment, there was a shorter mean duration of therapy (DOT) in the accepted group compared with the rejected group (2.26 days vs. 5.56 days; P<0.001). ASP interventions did not alter the length of hospital stay (LOS), 30-day mortality, 14-day Clostridium difficile infection (CDI), 30-day re-admissions and 14-day re-infection (all P>0.05). For empirical treatment, a shorter DOT (3.61 days vs. 6.25 days; P<0.001) and decreased 30-day all-cause mortality (P=0.003) and infection-related mortality (P=0.002) were observed among patients in the accepted group compared with the rejected group. There was no significant difference in LOS, 14-day CDI and 30-day re-admission (all P>0.05). In conclusion, acceptance of early interventions recommended by ASP in SGH was associated with a reduction in DOT without compromising patient safety. This is evident even during empirical therapy when not all clinical information was available.