Nephrotoxicity associated with intravenous colistin in critically ill patients

L-carnitine co-administration prevents colistin-induced mitochondrial permeability transition and reduces the risk of acute kidney injury in mice

Colistin is a polymyxin antibiotic currently experiencing renewed clinical interest due to its efficacy in the treatment of multidrug resistant (MDR) bacterial infections. The frequent onset of acute dose-dependent kidney injury, with the potential of leading to long-term renal damage, has limited its use and hampered adequate dosing regimens, increasing the risk of suboptimal plasma concentrations during treatment. The mechanism of colistin-induced renal toxicity has been postulated to stem from mitochondrial damage, yet there is no direct evidence of colistin acting as a mitochondrial toxin. The aim of this study was to evaluate whether colistin can directly induce mitochondrial toxicity and, if so, uncover the underlying molecular mechanism. We found that colistin leads to a rapid permeability transition of mitochondria isolated from mouse kidney that was fully prevented by co-incubation of the mitochondria with desensitizers of the mitochondrial transition pore cyclosporin A or L-carnitine. The protective effect of L-carnitine was confirmed in experiments in primary cultured mouse tubular cells. Consistently, the relative risk of colistin-induced kidney damage, calculated based on histological analysis as well as by the early marker of tubular kidney injury, Kim-1, was halved under co-administration with L-carnitine in vivo. Notably, L-carnitine neither affected the pharmacokinetics of colistin nor its antimicrobial activity against relevant bacterial strains. In conclusion, colistin targets the mitochondria and induces permeability transition thereof. L-carnitine prevents colistin-induced permeability transition in vitro. Moreover, L-carnitine co-administration confers partial nephroprotection in mice treated with colistin, without interfering with its pharmacokinetics and antibacterial activity.

Machine learning algorithms to predict colistin-induced nephrotoxicity from electronic health records in patients with multidrug-resistant Gram-negative infection

OBJECTIVES

Colistin-induced nephrotoxicity prolongs hospitalisation and increases mortality. The study aimed to construct machine learning models to predict colistin-induced nephrotoxicity in patients with multidrug-resistant Gram-negative infection.

METHODS

Patients receiving colistin from three hospitals in the Clinical Research Database were included. Data were divided into a derivation cohort (2011-2017) and a temporal validation cohort (2018-2020). Fifteen machine learning models were established by categorical boosting, light gradient boosting machine and random forest. Classifier performances were compared by the sensitivity, F1 score, Matthews correlation coefficient (MCC), area under the receiver operating characteristic (AUROC) curve, and area under the precision-recall curve (AUPRC). SHapley Additive exPlanations plots were drawn to understand feature importance and interactions.

RESULTS

The study included 1392 patients, with 360 (36.4%) and 165 (40.9%) experiencing nephrotoxicity in the derivation and temporal validation cohorts, respectively. The categorical boosting with oversampling achieved the highest performance with a sensitivity of 0.860, an F1 score of 0.740, an MCC of 0.533, an AUROC curve of 0.823, and an AUPRC of 0.737. The feature importance demonstrated that the days of colistin use, cumulative dose, daily dose, latest C-reactive protein, and baseline haemoglobin were the most important risk factors, especially for vulnerable patients. A cutoff colistin dose of 4.0 mg/kg body weight/d was identified for patients at higher risk of nephrotoxicity.

CONCLUSIONS

Machine learning techniques can be an early identification tool to predict colistin-induced nephrotoxicity. The observed interactions suggest a modification in dose adjustment guidelines. Future geographic and prospective validation studies are warranted to strengthen the real-world applicability.

A pharmacovigilance study of adverse events associated with polymyxins based on the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) database

BACKGROUND

Polymyxins have been regarded as last-line treatment for multidrug-resistant gram-negative bacterial infections. Nonetheless, concerns regarding toxicity persist. This study aimed to explore and compare potential adverse events (AEs) between colistin and polymyxin B (PMB).

METHODS

Polymyxins-related AEs were retrieved from the U.S. Food and Drug Administration Adverse Event Reporting System between 2004 and 2022. Potential signals were estimated by the reporting odds ratio (ROR), and subgroup analyses were preformed to adjust for potential factors in AEs with significant disproportionality.

RESULTS

Analysis of 3,915 records involving 718 patients revealed a higher disproportionality of renal and urinary disorders (ROR 1.62, 95% CI 1.01-2.59) and acute kidney injury (ROR 1.75, 95% CI 1.07-2.87) with colistin treatment. Conversely, colistin exhibited a lower risk for neurotoxicity (ROR 0.47, 95% CI 0.30-0.73). Seven cases of skin hyperpigmentation were reported with PMB, whereas none were reported with colistin. Over 80% of cases involving polymyxin-related AEs occurred during the first two weeks of therapies, with a median onset time of 4.5 days.

CONCLUSIONS

Patients received colistin displayed a higher potential risk of nephrotoxicity but a lower risk of neurotoxicity. Clinicians should be vigilant in monitoring the AEs of hyperpigmentation disorders induced by PMB.

Prevalence of polymyxin-induced nephrotoxicity and its predictors in critically ill adult patients: A meta-analysis

BACKGROUND

Polymyxin-induced nephrotoxicity is a major safety concern in clinical practice due to long-term adverse outcomes and high mortality.

AIM

To conducted a systematic review and meta-analysis of the prevalence and potential predictors of polymyxin-induced nephrotoxicity in adult intensive care unit (ICU) patients.

METHODS

PubMed, EMBASE, the Cochrane Library and Reference Citation Analysis database were searched for relevant studies from inception through May 30, 2022. The pooled prevalence of polymyxin-induced nephrotoxicity and pooled risk ratios of associated factors were analysed using a random-effects or fixed-effects model by Stata SE ver. 12.1. Additionally, subgroup analyses and meta-regression were conducted to assess heterogeneity.

RESULTS

A total of 89 studies involving 12234 critically ill adult patients were included in the meta-analysis. The overall pooled incidence of polymyxin-induced nephrotoxicity was 34.8%. The pooled prevalence of colistin-induced nephrotoxicity was not higher than that of polymyxin B (PMB)-induced nephrotoxicity. The subgroup analyses showed that nephrotoxicity was significantly associated with dosing interval, nephrotoxicity criteria, age, publication year, study quality and sample size, which were confirmed in the univariable meta-regression analysis. Nephrotoxicity was significantly increased when the total daily dose was divided into 2 doses but not 3 or 4 doses. Furthermore, older age, the presence of sepsis or septic shock, hypoalbuminemia, and concomitant vancomycin or vasopressor use were independent risk factors for polymyxin-induced nephrotoxicity, while an elevated baseline glomerular filtration rate was a protective factor against colistin-induced nephrotoxicity.

CONCLUSION

Our findings indicated that the incidence of polymyxin-induced nephrotoxicity among ICU patients was high. It emphasizes the importance of additional efforts to manage ICU patients receiving polymyxins to decrease the risk of adverse outcomes.

Does Monitoring Total and Free Polymyxin B1 Plasma Concentrations Predict Polymyxin B-Induced Nephrotoxicity? A Retrospective Study in Critically Ill Patients

INTRODUCTION

The correlation between total and free polymyxin B (PMB including PMB1 and PMB2) exposure in vivo and acute kidney injury (AKI) remains obscure. This study explores the relationships between plasma exposure of PMB1 and PMB2 and nephrotoxicity, and investigates the risk factors for PMB-induced acute kidney injury (AKI) in critically ill patients.

METHODS

Critically ill patients who used PMB and met the criteria were enrolled. The total plasma concentration and plasma binding of PMB1 and PMB2 were analysed by liquid chromatography-tandem mass spectrometry and equilibrium dialysis.

RESULTS

A total of 89 patients were finally included, and AKI developed in 28.1% of them. The peak concentration of PMB1 (C_max (B1)) (adjusted odds ratio (AOR) = 1.68, 95% CI 1.08-2.62, p = 0.023), baseline BUN level (AOR = 1.08, 95% CI 1.01-1.16, p = 0.039) and hypertension (AOR = 3.73, 95% CI 1.21-11.54, p = 0.022) were independent risk factors for PMB-induced AKI. The area under the ROC curve of the model was 0.799. When C_max (B1) was 5.23 μg/ml or more, the probability of AKI was higher than 50%. The ratio of PMB1/PMB2 decreased after PMB preparation entered into the body. The protein binding rate in critically ill patients indicated significant individual differences. Free C_max (B) and free C_max (B1) levels in the AKI group were significantly (p < 0.05) higher than those in the non-AKI group. Total and free concentrations of PMB in patients showed a positive correlation.

CONCLUSIONS

Both the ROC curve and logistic regression model showed that C_max (B1) was a good predictor for the probability of PMB-induced AKI. Early therapeutic drug monitoring (TDM) of PMB should be considered in critically ill patients. Compared with C_min (B), C_max (B) and C_max (B1) may be helpful for the early prediction of PMB-induced AKI in critically ill patients.

Colistin-Induced Acute Kidney Injury and the Effect on Survival in Patients with Multidrug-Resistant Gram-Negative Infections: Significance of Drug Doses Adjusted to Ideal Body Weight

Background

Colistin is a lifesaving treatment for multidrug-resistant Gram-negative bacterial (MDR-GNB) infections along with its well-known nephrotoxicity. The controversy of colistin-induced acute kidney injury (AKI) on mortality is noted. This study aimed to determine the risk factors and impact of AKI on the survival and significance of colistin dosage.

Methods

A retrospective cohort study was performed in adult patients who received intravenous colistin for MDR-GNB treatment between June 2015 and June 2017. Factors influencing colistin-induced AKI and survival were evaluated by Cox regression analysis. Cut-off levels of the colistin dose per ideal body weight (IBW) that significantly affected clinical outcomes were assessed with linearity trends and receiver operating characteristic analyses.

Results

AKI occurred in 68.5% of 412 enrolled patients with an incidence rate of 10.6 per 100 patients-days and a median time was 6 (3–13) days. Stages I–III of AKI were 38.3, 24.5, and 37.2%. Factors associated with colistin-induced AKI were advanced age, high serum bilirubin, AKI presented before colistin administration, increased daily colistin doses per IBW, and concomitant use of nephrotoxic drugs. Colistin-induced AKI was related to mortality (HR 1.74, 95% CI 1.06–2.86, p=0.028). In the non-AKI before colistin usage subgroup, the total dose and total dose/IBW were >1,500–2,000 mg and 30–35 mg/kg to benefit mortality reduction but were <2,500–3,000 mg and 45–50 mg/kg for risk reduction of AKI. A daily colistin dose/IBW >4.5 mg/kg/day also increased the risk of AKI. In the AKI developed before colistin subgroup, the cut-off values of total colistin dose >1250–1350 mg and total dose/IBW >23.5–24 mg/kg demonstrated significant risks of AKI.

Conclusion

The incidence of AKI after colistin administration was high and impacted mortality. Prevention and early correction of these related factors are mandatory. Careful use of colistin was also both beneficial in mortality and AKI reductions.

Characteristics, Influencing Factors, Predictive Scoring System, and Outcomes of the Patients with Nephrotoxicity Associated with Administration of Intravenous Colistin

Multidrug-resistant Gram-negative infection is a major global public health threat. Currently, colistin is considered the last-resort treatment despite its nephrotoxicity. The purpose of this study was to estimate the incidence, characteristics, and influencing factors and to develop a prediction model for colistin-associated nephrotoxicity. A retrospective study was conducted in the university hospital in the South of Thailand from December 2015 to June 2019. A total of 381 patients (median age (IQR) of 64 (51–62) years) were analyzed. Overall, 282 (74%) had nephrotoxicity according to the Kidney Disease: Improving Global Outcomes (KDIGO) classification. In-hospital, 30-day mortality rates and cost of hospital admission were significantly higher among those with nephrotoxicity. Age > 60 years, comorbidities, serum albumin less than 3.5 g/dL, and concomitant nephrotoxic use were significantly associated with colistin-associated nephrotoxicity with adjusted OR (95% CI) 2.01 (1.23–2.45), 1.85 (1.18–3.6), 1.68 (1.09–2.99), and 1.77 (1.10–2.97), respectively. The prediction model for high-risk colistin-associated nephrotoxicity was identified with good overall performance (specificity of 79.6% (95% CI 70.3–87.1) and positive predictive value of 92.1% (95% CI 88.0–95.1)). In conclusion, the incidence of colistin-associated nephrotoxicity was high and incurred significant morbidity, mortality, and economic burden. Our predictive scoring system is relatively simple and useful for optimizing colistin therapy.

Colistin Nephrotoxicity-Age and Baseline kidney Functions Hold the Key

Introduction:

With the emergence of multidrug-resistant gram-negative bacterial infections, there has been a surge in the use of Colistin in recent times. The most important side effect of Colistin use is its nephrotoxicity. The study was designed to assess the effect on kidney function and the risk factors for nephrotoxicity in patients treated with Colistin.

Methods:

The study is a retrospective one, which included patients who received Colistin for more than 48 hours. The estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) four-variable equation and acute kidney injury (AKI) was diagnosed as per the Kidney Disease Improving Global Outcome (KDIGO) criteria.

Results:

Of the 150 patients studied, 59 patients (39.2%) developed AKI within a median period of 4 days (Range 2–20 days) of initiation of Colistin. Age, eGFR at the start of therapy and requirement of vasopressor support for treatment of septic shock were the most important risk factors associated with nephrotoxicity. Among patients with AKI, nearly half had only mild worsening of renal functions to KDIGO AKI stage 1. Nearly 75% of patients with AKI had complete or partial recovery of renal functions after stopping Colistin.

Conclusion:

Colistin has significant nephrotoxicity, the risk being higher with older age and baseline renal dysfunction. It is important to monitor renal functions early and at regular intervals after initiating therapy.

Risk factors and mortality associated with multidrug-resistant gram-negative bacterial infection in adult patients with abdominal surgery

BACKGROUND

Multidrug-resistant (MDR) gram-negative bacterial (GNB) infections remain a significant cause of morbidity and mortality among surgical patients. The objective of our study was to recognize the risk factors for MDR GNB infection in patients with abdominal surgery and determine the predictors independently associated with death.

METHODS

From 2010 to 2017, a retrospective cohort study was conducted among patients with abdominal surgery admitted in surgical intensive care unit (ICU). Patients with GNB infections were included for analyses.

RESULTS

A total of 364 patients with abdominal surgery experienced GNB infections, among them, 117 (32.1%) were MDR GNB infection. Of 133 MDR GNB isolates, the most frequent isolate was Escherichia coli (45.1%). Patients with MDR GNB infection had significantly longer ventilator days and hospital stay, as well as higher 30-day and in-hospital mortality compared to non-MDR GNB patients. Multivariable analysis showed longer length of pre-ICU stay, surgical re-exploration, receipt of group 2 carbapenems (e.g. imipenem, meropenem and doripenem) and fluoroquinolones, and higher total bilirubin were independent risk factors for the acquisition of MDR GNB infection. Predictors for 30-day mortality among patients with MDR GNB infection were chronic kidney disease, receipt of group 2 carbapenems and inappropriate empirical antimicrobial therapy.

CONCLUSIONS

This study provides important information about the risk factors for subsequent MDR GNB infection and 30-day mortality among the patients with abdominal surgery.

Acute Kidney Injury related to intravenous Colistin Use in Lebanese Hospitalized Patients: Incidence and Associated Factors

INTRODUCTION

Colistin use has risen because of the emergence of Gram-negative resistant infections. Acute kidney injury (AKI) remains a treatment-limiting factor for widespread colistin clinical use. This study aimed to determine the incidence and the factors associated with the development of colistin-induced AKI.

METHOD

A retrospective observational study was conducted by reviewing files of adult patients, with normal kidneys function between January 2015 to March 2019 at a university hospital located in Beirut city. AKI was defined based on KDIGO criteria. Several variables were tested to determine independent factors that were associated with colistin induced AKI.

RESULTS

A total of 113 patients were included in this study. AKI occurred in 53 patients (46.9%). The Charlson Comorbidity Index (CCI) was significantly higher in the AKI group (2.26, P-value = 0.026). In the multivariate analysis, low serum albumen was found as an independent significant predictor for AKI (OR=.065, 95%CI: .013-.337, P-value=0.001). Moreover, the risk for AKI increased by 2 folds (OR=2.019, 95%CI: 1.094-3.728, P-value: 0.025), when two or more nephrotoxic agents were administered simultaneously with colistin. Patient's age was also found as significant predictor for AKI (OR=1.034, 95% CI:1-1.07), with a cut-off value of 58.5 year-old.

CONCLUSION

This study demonstrated that the use of concomitant use of two or more nephrotoxic drugs, patient's age of 58.5 or more, and the presence of hypoalbuminemia were independent factors for the development of colistin-induced AKI. These factors should be therefore taken into consideration when prescribing colistin in clinical practice to reduce the risk of AKI.

Systematic review on estimated rates of nephrotoxicity and neurotoxicity in patients treated with polymyxins

BACKGROUND

Nephrotoxicity and neurotoxicity are commonly associated with polymyxin treatment; however, the emergence of multidrug-resistant Gram-negative bacteria with limited therapeutic options has resulted in increased use of polymyxins.

OBJECTIVES

To determine the rates of nephrotoxicity and neurotoxicity during polymyxin treatment and whether any factors influence these.

DATA SOURCES

Medline, Embase and Cochrane Library databases were searched on 2 January 2020.

STUDY ELIGIBILITY CRITERIA

Studies reporting nephrotoxicity and/or neurotoxicity rates in patients with infections treated with polymyxins were included. Reviews, meta-analyses and reports not in English were excluded.

PARTICIPANTS

Patients hospitalized with infections treated with systemic or inhaled polymyxins were included. For comparative analyses, patients treated with non-polymyxin-based regimens were also included.

METHODS

Meta-analyses were performed using a random-effects model; subgroup meta-analyses were conducted where data permitted using a mixed-effects model.

RESULTS

In total, 237 reports of randomized controlled trials, cohort and case-control studies were eligible for inclusion; most were single-arm observational studies. Nephrotoxic events in 35,569 patients receiving polymyxins were analysed. Overall nephrotoxicity rate was 0.282 (95% confidence interval (CI) 0.259-0.307). When excluding studies where >50% of patients received inhaled-only polymyxin treatment or nephrotoxicity assessment was by methods other than internationally recognized criteria (RIFLE, KDIGO or AKIN), the nephrotoxicity rate was 0.391 (95% CI 0.364-0.419). The odds of nephrotoxicity were greater with polymyxin therapies compared to non-polymyxin-based regimens (odds ratio 2.23 (95% CI 1.58-3.15); p < 0.001). Meta-analyses showed a significant effect of polymyxin type, dose, patient age, number of concomitant nephrotoxins and use of diuretics, glycopeptides or vasopressors on the rate of nephrotoxicity. Polymyxin therapies were not associated with a significantly different rate of neurotoxicity than non-polymyxin-based regimens (p 0.051). The overall rate of neurotoxicity during polymyxin therapy was 0.030 (95% CI 0.020-0.043).

CONCLUSIONS

Polymyxins are associated with a higher risk of nephrotoxicity than non-polymyxin-based regimens.

Polymyxin-induced nephrotoxicity and its predictors: a systematic review and meta-analysis of studies conducted using RIFLE criteria of acute kidney injury

Polymyxins are last-resort antibiotics re-emerged to treat infections caused by multidrug resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacterial infections. However, polymyxin-associated nephrotoxicity has become the main safety concern. Therefore, we conducted this systematic review and meta-analysis on polymyxin-induced nephrotoxicity and its predictors using studies conducted based on the validated RIFLE (Risk, Injury, Failure, Loss of Function and End-stage renal disease) criteria of acute kidney damage. Literature search was carried out through visiting legitimate databases and indexing services including PubMed, MEDLINE (Ovid®), EMBASE (Ovid®), and Scopus to retrieve relevant studies. Following screening and eligibility evaluation, relevant data were extracted from included studies and analyzed using STATA 15.0 and Rev-Man 5.3. Inverse variance method with random effects pooling model was used for the analysis of outcome measures at 95% confidence interval. Besides, meta-regression, meta-influence, and publication bias analyses were conducted. A total of 48 studies involving 6,199 adult patients aged ≥ 18 years were included for systematic review and meta-analysis. The pooled incidence of polymyxin-induced nephrotoxicity was found to be 45% (95% CI: 41- 49%; I² = 92.52%). Stratifying with RIFLE severity scales, pooled estimates of polymyxin-treated patients identified as 'risk', 'injury' and 'failure' were 17% (95% CI: 14-20%), 13% (95% CI: 11-15%), and 10% (95% CI: 9-11%), respectively. Besides, the pooled incidence of colistin-induced nephrotoxicity was about 48% (95% CI: 42-54%), whereas that of polymyxin B was 38% (95% CI: 32-44%). Likewise, colistin had 37% increased risk of developing nephrotoxicity compared to the polymyxin B treated cohorts (RR = 1.37, 95% CI: 1.13-1.67; I² = 57%). Older age (AOR = 1.03, 95% CI: 1.01-1.05), daily dose (AOR = 1.46, 95% CI: 1.09-1.96), underlying diabetes mellitus (AOR = 1.81, 95% CI: 1.25-2.63), and concomitant nephrotoxic drugs (AOR = 2.31, 95% CI: 1.79-3.00) were independent risk factors for polymyxin-induced nephrotoxicity. Patients with high serum albumin level were less likely (AOR = 0.69, 95% CI: 0.56-0.85] to experience nephrotoxicity compared to those with low albumin level. Despite the resurgence of these antibiotics for the chemotherapy of MDR/XDR-Gram-negative superbugs, the high incidence of nephrotoxicity has become a contemporary clinical concern. Being elderly, high daily dose, having underlying diseases such as diabetes, and use of concomitant nephrotoxic drugs were independent predictors of nephrotoxicity. Therefore, therapeutic drug monitoring should be done to these patients to outweigh the potential benefits of polymyxin therapy from its risk.

Colistin co-administration with other nephrotoxins: experience of teaching hospital of Latvia

Background Colistin is a potentially nephrotoxic antibiotic used for the management of multidrug-resistant bacterial infections in critically ill patients. Co-administration with other nephrotoxins was reported as a potentially modifiable risk factor of colistin acute kidney injury. Objective To establish the role of colistin dosing and co-medications in development of colistin kidney injury. Setting Community teaching hospital in Latvia. Method Adult patients from intensive care units with diagnosed Gram-negative bacterial infections, undergoing colistin treatment for longer than 72 h, and not receiving renal replacement therapy were included in this retrospective study. Main outcome measure Colistin nephrotoxicity was defined as an increase in the serum creatinine level by at least 50% from the baseline after ≥ 48 h. Results In 73 of 87 cases, Acinetobacter baumannii pneumonia was diagnosed. The nephrotoxicity rate was 27.6% with a median onset of 8 days. In 79% of the cases, colistin was co-administrated with at least one potentially nephrotoxic agent. The most used nephrotoxins were loop diuretics (44 cases), non-steroidal anti-inflammatory drugs (19 cases) and vancomycin (11 cases). The use of nephrotoxins was similar in patients with colistin nephrotoxicity (group-1) and without it (group-2). Carbapenems were more common in group-2 (37% vs 62%, p = 0.004) and a colistin loading dose of 9 MU in group-1 (87% vs 62%, p = 0.027). However, in the multifactor regression analysis, the protective role of carbapenems was not confirmed. Conclusion Potentially nephrotoxic agents are commonly co-administrated with colistin. This study failed to prove their role in the development of acute kidney injury.

Retrospective Study of Nephrotoxicity Rate among Adult Patients Receiving Colistin Compared to β-lactam Antibiotics

Purpose

Patients receiving colistin for carbapenem-resistant gram-negative bacteria (CR-GNB) infections generally have multiple risk factors for nephrotoxicity, so it might be possible that colistin may be erroneously blamed for the nephrotoxicity.

Materials and methods

We retrospectively analyzed case records of patients who received colistin and those who received antibiotics other than colistin [carbapenem or β-lactam–β-lactamases inhibitors (βL–βLI)] for gram-negative bacteremia. Those patients with preexisting renal failure and those who received antibiotics for <72 hours were excluded from the study. Nephrotoxicity was assessed using the risk of renal dysfunction, injury to the kidney, failure of kidney function, loss of kidney function, end-stage kidney disease (RIFLE) criteria.

Results

Out of the 222 patients, the colistin arm had 118 and the noncolistin arm had 104 patients. Even though the colistin arm had significantly higher number of sicker patients with neutropenia (40.7% vs 14.4%, p = 0.0001), mechanical ventilation (0.0001), having lines (0.0001), on inotropes (0.003), receiving other nephrotoxic drugs (0.0001), and higher Pitt score (p = 0.0001), there was no significant difference in the nephrotoxicity between the two arms (10.2% vs 9.6%, p = 0.89). Logistical regression showed a higher Pitt bacteremia score (p = 0.03) and a higher Charlson comorbidity index (p = 0.02), but not colistin administration (p = 0.32), were independently associated with nephrotoxicity.

Conclusion

Administration of colistin was not associated with higher rates of nephrotoxicity than carbapenems or βL–βLI agents.

How to cite this article

Ghafur A, Bansal N, Devarajan V, Raja T, Easow J, Raja MA, et al. Retrospective Study of Nephrotoxicity Rate among Adult Patients Receiving Colistin Compared to β-lactam Antibiotics. IJCCM 2019;23(11):518–522.

Nephrotoxicity prevalence in patients treated with polymyxins: a systematic review with meta-analysis of observational studies

Colistin and polymyxin B are increasingly reintroduced in clinical practice due to the absence of effective antibiotics for the treatment of emerging infections caused by gram-negative bacteria. The synthesis of current evidence on the characteristics of polymyxins, especially regarding nephrotoxicity, is necessary. This study aims to conduct a systematic review and meta-analysis of cohort-type observational studies in order to identify the prevalence of nephrotoxicity in patients treated with either colistin or polymyxin B. PubMed, Scopus, and DOAJ electronic databases were searched, and manual searches were done. Cohort studies evaluating renal damage (nephrotoxicity) in adult patients caused by colistin or polymyxin B were included. Meta-analyses of the prevalence of nephrotoxicity as well as cumulative meta-analysis and meta-regression were conducted. After the systematic searches, 95 cohorts (n = 7911 patients) were included for analysis. The nephrotoxicity prevalence was 26.7% [confidence interval (CI) 95%: 22.8-30.9%] for colistin and 29.8% (CI 23.8-36.7%) for polymyxin B (P = 0.720). The publication year of the studies, the criteria used to classify renal damage, and the nephrotoxicity as primary or secondary outcome showed a significant influence on the adverse event rates.

Cost-effectiveness analysis of low versus high dose colistin in the treatment of multi-drug resistant pneumonia in Saudi Arabia

Background Gram negative pathogens are increasingly resistant to commonly used first line antibiotics and colistin is in most cases the only medicine available. There is very limited information available comparing the effectiveness and costs of low versus high dose colistin with studies showing efficacy with both doses and with variable levels of adverse effects. The absence of a definite dosing strategy makes a model to compare low dose and high dose colistin invaluable in making decisions regarding the appropriate use of colistin. Objective This study was designed to evaluate the cost effectiveness of low versus high dose colistin in the treatment of Pneumonia caused by colistin-only sensitive gram negative bacteria from the perspective of a tertiary care hospital in Saudi Arabia. Setting 300-bed tertiary care hospital in Saudi Arabia. Method A retrospective review was conducted to compare the costs and outcomes of treatment of pneumonia with low versus high dose colistin. The model followed an average patient from initiation of treatment until clinical cure or failure. Main outcome measures The main outcomes were cure, nephrotoxicity, total direct costs per episode, cost per additional cure and cost per nephrotoxicity avoided. Results There was no significant difference between high and low dose colistin with regards to clinical cure (30% vs. 21%; p = 0.292). Significantly more patients experienced nephrotoxicity with high versus low dose colistin (30% vs. 8%; p = 0.004). With low dose colistin the incremental costs per nephrotoxicity avoided was SAR-3056.28. One-way sensitivity analyses did not change the overall results. Conclusion Low dose was not inferior to high dose colistin in terms of clinical cure and had a lower incidence of nephrotoxicity resulting in significant cost avoidance.

Hypoalbuminemia as a predictor of acute kidney injury during colistin treatment

This study aimed to assess the predictors of acute kidney injury (AKI) during colistin therapy in a cohort of patients with bloodstream infections (BSI) due to colistin-susceptible Gram-negative bacteria, focusing on the role of serum albumin levels. The study consisted of two parts: (1) a multicentre retrospective clinical study to assess the predictors of AKI during colistin therapy, defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria; and (2) bioinformatic and biochemical characterization of the possible interaction between human serum albumin and colistin. Among the 170 patients included in the study, 71 (42%), 35 (21%), and 11 (6%) developed KDIGO stage 1 (K1-AKI), KDIGO stage 2 (K2-AKI), and KDIGO stage 3 (K3-AKI), respectively. In multivariable analyses, serum albumin <2.5 g/dL was independently associated with K1-AKI (subdistribution hazard ratio [sHR] 1.85, 95% confidence interval [CI] 1.17-2.93, p = 0.009) and K2-AKI (sHR 2.37, 95% CI 1.15-4.87, p = 0.019). Bioinformatic and biochemical analyses provided additional information nurturing the discussion on how hypoalbuminemia favors development of AKI during colistin therapy. In conclusion, severe hypoalbuminemia independently predicted AKI during colistin therapy in a large cohort of patients with BSI due to colistin-susceptible Gram-negative bacteria. Further study is needed to clarify the underlying causal pathways.

Adding a C-terminal Cysteine (CTC) Can Enhance the Bactericidal Activity of Three Different Antimicrobial Peptides

The emergence of antibiotic-resistant bacteria has threatened our health worldwide. There is an urgent need for novel antibiotics. Previously, we identified a novel 37-mer antimicrobial peptide (AMP), HBcARD, with broad spectrum antimicrobial activity. Here, we improved the efficacy of HBcARD, by re-engineering the peptide, including the addition of a new cysteine to its C-terminus (CTC). The new 28-mer derivative, D-150-177C, contains all D-form arginines, in addition to a C-terminal cycteine. This peptide can kill antibiotic-resistant clinical isolates of Gram-negative bacteria, and is more potent than the parental HBcARD peptide in a mouse sepsis model. In another lung infection mouse model, D-150-177C showed protection efficacy against colistin-resistant Acinetobacter baumannii. Unlike colistin, we observed no acute toxicity of D-150-177C in vivo. Interestingly, we found that CTC modification could enhance the antibacterial activity of several other AMPs, such as buforinII and lysin. The potential application and mechanism of this CTC method as a general approach to improving drug efficacy, warrants further investigation in the future.

Colistin nephrotoxicity in the ICU: Is it different in the geriatric patients?

OBJECTIVE

Most significant side effect of colistin therapy which is used for the treatment of multi-drug resistant Gram-negative infections is nephrotoxicity. Our aim was to investigate the differences of colistin nephrotoxicity between the geriatric age group (≥65 years) and the younger age group (<65 years) in critically ill medical intensive care unit (ICU) patients.

MATERIAL AND METHOD

The medical records of the 76 patients who were taken colistin therapy due to multi-resistant Gram-negative infections between January 2010 and June 2014 in the our medical ICU were retrospectively investigated. Demographic characteristics, reasons for colistin use, daily colistin dose, duration of colistin use were recorded. Colistin-dependent renal dysfunction was evaluated according to the risk, injury, failure, loss and end-stage renal failure (RIFLE) criterias.

RESULTS

The median age of the patients was 65 (65.8% male). Nephrotoxicity was developed in 36 (47.4%) patients. Thirty-nine (51.3%) patients were in geriatric age group, 37 (48.7%) were in younger age group. In geriatric age group, the rates of male gender (53.8 vs 78.4%, p = 0.031), pulmonary (48.7 vs 16.2%, p = 0.003) and cardiac diseases (71.8 vs 29.7%, p < 0.001), post-nephrotoxicity BUN levels (p = 0.023) and urine output during nephrotoxicity (p = 0.016) were higher than younger age group. Nephrotoxicity was developed in 22 (56.4%) patients of geriatric age group, and in 14 (37.8%) patients in younger age group (p = 0.115). The presence of cardiac disease, renal pathology and high creatinin value on admission, daily amount of colistin per body mass, total amount of colistin, use of colistin for pulmonary infection, use of amphotericin and vasopressor on admission were found as risk factors for colistin nephrotoxicity development in all study group; the daily amount of colistin per body mass (risk ratio:0.41; 95% CI 0.19-0.89) and vasopressor use during hospitalization were found independent risk factors (risk ratio:13.54; 95% CI 2.21-83.09).

CONCLUSION

In our study, in geriatric patient group colistin nephrotoxicity was not different from the younger age group. In the ICU, the age for nephrotoxicity does not appear to be a point to be considered for the initiation of colistin.

Serum Cystatin C for Evaluation of Acute Kidney Injury in Adults Treated with Colistin

Objective

Recent studies have shown that serum cystatin C (Cys C) is a better marker for measuring the glomerular filtration rate and may rise more quickly with acute kidney injury (AKI). The purpose of this study was to evaluate the clinical application of serum Cys C to predict colistin-induced nephrotoxicity in comparison with serum creatinine (SCr).

Methods

Thirty-two adult patients with no history of acute or chronic kidney injury having been planned to receive intravenous colistin for an anticipated duration of at least 1 week for any indication were recruited. At baseline and 5 days after colistin treatment, serum Cys C as well as creatinine levels were measured. The incidence of colistin-induced acute renal failure was defined according to the AKIN criteria for SCr. Rise in concentration of Cys C by more than 10% from baseline considered as AKI.

Findings

Colistin-induced nephrotoxicity (defined as SCr ≥0.3 mg/dl) occurred in 6 patients (18.8%). A Cys C increase concentration ≥10% after 5 days of colistin treatment was detected in 15 patients (46.9%). There was a poor agreement between the presence and absence of any SCr-AKI and Cys C-AKI (κ = 0.28, P = 0.04).

Conclusion

Serum Cys C is a better marker of renal function in early stages of AKI and predictive of persistent AKI on colistin treatment.

Good tolerability of high dose colistin-based therapy in patients with haematological malignancies

PURPOSE

Colistin is usually the only drug fully active against multi-drug resistant Gram-negative bacteria, but its nephrotoxicity might limit its use. Recent pharmacokinetic/pharmacodynamic data suggest that high dose of colistin, preceded by a loading dose, are needed to maximize its antibacterial effect. The aim of this study was to determine the safety of high doses colistin, in haematology population.

METHODS

A retrospective review of haematology patients who received high dose colistin-based therapy in years 2011-2016 was performed. Nephrotoxicity was assessed using RIFLE criteria.

RESULTS

Thirty patients who received 38 courses of colistin were included in the study. Colistin was always administered together with other antibiotics. Colistin was well tolerated, with one case of neurological toxicity and one of cutaneous reaction. There were 22 (58%) treatment cycles without any nephrotoxicity, even though during 16 of these cycles other nephrotoxic drugs were administered. Severe (injury or failure) renal toxicity occurred during 6 (16%) treatment courses, requiring colistin discontinuation in 2 patients and colistin dose reduction in 1. Poorer renal function at baseline and younger age were the only variables associated with increased renal toxicity (p = 0.011 and p = 0.031, respectively). Overall mortality was 18% (7/38) and 29% (11/38) at 7 and 30 days after the treatment onset.

CONCLUSIONS

In adult haematology population, high dose colistin therapy is safe and efficacious, despite high frequency of concomitant nephrotoxic treatment.

Defining the incidence and risk factors of colistin-induced acute kidney injury by KDIGO criteria

Background

Acute kidney injury (AKI) remains a treatment-limiting toxicity of colistin. Recently developed clinical practice guidelines from the Kidney Disease: Improving Global Outcomes (KDIGO) group have harmonized definitions of AKI, but have not been widely applied to patients receiving colistin.

Methods

We retrospectively defined AKI by KDIGO definitions among adult patients receiving intravenous colistin for ≥ 3 days. Risk factors for AKI within 48 hours and 7 days of initiating colistin were determined by multivariable logistic regression.

Results

Among 249 patients treated with colistin, rates of AKI were 12% and 29% at 48 hours and 7 days, respectively. At 48 hours, patients in the intensive care unit were at increased risk for AKI. Within 7 days, colistin daily doses >5mg/kg, chronic liver disease, and concomitant vancomycin were independent predictors. Seven percent of patients required renal replacement therapy at a median of 5 days (range: 3–7) following colistin initiation.

Conclusion

Safe use of colistin is promoted by early detection of AKI with KDIGO criteria, avoiding nephrotoxins, and limiting duration of therapy.

Colistin Nephrotoxicity in Adults: Single Centre Large Series from India

Context:

Limited Indian data are available on the rate of colistin nephrotoxicity and other risk factors contributing to the development of this important side effect.

Aim:

This study aims to generate data on colistin nephrotoxicity from a large cohort of Indian patients.

Design:

Retrospective cohort study.

Materials and Methods:

Case record analysis of patients who received colistin, in an oncology center in India, between January 2011 and December 2015. Nephrotoxicity was assessed using risk, injury, failure, loss, and end-stage (RIFLE) criteria.

Statistical Analysis:

P < 0.05 was considered as statistically significant.

Results:

Out of the 229 patients, 13.1% (30/229) developed abnormal RIFLE. Abnormal RIFLE group (n = 30), in comparison to the normal renal function group (n = 199), had higher number of patients in intensive care unit (ICU) (96% vs. 79%, P = 0.02), higher Acute Physiology and Chronic Health Evaluation (APACHE II) score (23 vs. 19 P = 0.0001), Charlson score (5.9 vs. 4.3, P = 0.001), mechanical ventilation (90% vs. 67%, P = 0.016), 28 days mortality (63% vs. 25%, P = 0.0001), and abnormal baseline creatinine (36% vs. 8%, P = 0.001). Coadministration of vancomycin had higher rates of nephrotoxicity (P = 0.039). There was no significant difference in nephrotoxicity between 6 and 9 MU/day dosing pattern (8.8% vs. 13.8%, P = 0.058).

Conclusion:

Nephrotoxicity rate in our retrospective single center large series of patients receiving colistin was 13.1%. Patients with abnormal baseline creatinine, ICU stay, and higher disease severity are at higher risk of nephrotoxicity while on colistin. A daily dose of 9 million does not significantly increase nephrotoxicity compared to the 6 million. Concomitant administration of vancomycin with colistin increases the risk of nephrotoxicity.

Predicting the risk of nephrotoxicity in patients receiving colistimethate sodium: a multicentre, retrospective, cohort study

OBJECTIVES

With increasing rates of infections caused by MDR Gram-negative organisms, clinicians resort to older agents such as colistimethate sodium (CMS) despite a significant risk of nephrotoxicity. Several risk factors for CMS-associated nephrotoxicity have been reported, but they have yet to be validated. We compared the performance of published mathematical models in predicting the risk of CMS-associated nephrotoxicity.

METHODS

In a multicentre, retrospective, cohort study, adult patients (≥18 years of age) were evaluated from five large academic medical centres in the USA. Patients with normal renal function (baseline serum creatinine ≤1.5 mg/dL) who received intravenous CMS for ≥72 h were followed for up to 30 days. The development of nephrotoxicity was as defined by the RIFLE criteria. Each published model was conditioned using patient-specific variables to predict the risk of nephrotoxicity. The predictive performance of the models was evaluated using the observed-to-expected (O/E) ratio. The most significant cut-off threshold for stratifying patients into high and low risk of nephrotoxicity was identified using classification and regression tree analysis.

RESULTS

A total of 106 patients were examined (mean age 53.3 ± 14.9 years, 66% male); the overall observed nephrotoxicity rate was 52.8%. We identified a simple model demonstrating reasonable overall nephrotoxicity risk assessment [O/E ratio of 1.07 (95% CI = 0.81-1.39)] and high sensitivity (92.9%) in predicting nephrotoxicity development in patients on CMS therapy.

CONCLUSIONS

We identified a model that could be incorporated into patient management strategies to reduce the risk of nephrotoxicity in patients requiring CMS therapy.

Evaluation of Risk Factors for Intravenous Colistin Use-related Nephrotoxicity

OBJECTIVES

We investigated the incidence of and risk factors for nephrotoxicity in patients using intravenous colistin.

METHODS

This retrospective, observational study was conducted at Karadeniz Technical University, Faculty of Medicine, clinics and intensive care unit between 1 January 2009 and 1 January 2013. Intravenous colistin was administered to 133 patients at a dose of 2.5-5.0 mg/kg/day.

RESULTS

The patients mean age was 54.3±19.1 years and the mean duration of treatment was 13.5±3.6 days. Nephrotoxicity developed in 5.0±2.8 days in 38 (28.6%) patients. Based on RIFLE (risk, injury, failure, loss of kidney function, and end-stage kidney disease) criteria, 15 (39.5%) patients were class 1, 17 (44.7%) were class 2, six (15.8%) were class 3, and none were class 4. The mean duration of development of nephrotoxicity was 5.0±2.8 days. Hemodialysis requirement was observed in two (5.2%) of the 38 patients who developed nephrotoxicity. In these cases, colistin therapy was not discontinued. Nephrotoxicity was correlated with advanced age, high pretreatment serum creatinine levels, diabetes mellitus, and chronic obstructive pulmonary disease.

CONCLUSIONS

The use of colistin is relatively safe for patients that have normal renal functions. However, better standardization of the definition of nephrotoxicity in those patients with the use of scoring systems and close monitoring are necessary.

Efficacy and Safety of a Colistin Loading Dose, High-Dose Maintenance Regimen in Critically Ill Patients With Multidrug-Resistant Gram-Negative Pneumonia

INTRODUCTION

Emergence of multidrug-resistant (MDR) gram-negative (GN) pathogens and lack of novel antibiotics have increased the use of colistin, despite unknown optimal dosing. This study aimed to evaluate the safety and efficacy of a colistin loading dose, high-dose (LDHD) maintenance regimen in patients with MDR-GN pneumonia.

METHODS

A retrospective cohort analysis was performed comparing critically ill patients with MDR-GN pneumonia pre- and postimplementation of a colistin LDHD guideline with a primary outcome of clinical cure. Safety was assessed using incidence of acute kidney injury (AKI) based on RIFLE (risk, injury, failure, loss, end-stage renal disease) criteria.

RESULTS

Seventy-two patients met the inclusion criteria (42 preimplementation and 30 postimplementation). Clinical cure was achieved in 23 (55%) patients in the preimplementation group and 20 (67%) patients in the postimplementation group ( P = .31). AKI occurred in 50% of the patients during the preimplementation period and 58% during the postimplementation period ( P = .59) with no difference in initiation rates of renal replacement therapy.

CONCLUSION

The increased clinical cure rate after implementation of the colistin LDHD guideline did not reach statistical significance. The LDHD guideline, however, was not associated with an increased incidence of AKI, despite higher intravenous colistin doses. Opportunity exists to optimize colistin dosage while balancing toxicity, but larger studies are warranted.

Is colistin effective in the treatment of infections caused by multidrug-resistant (MDR) or extremely drug-resistant (XDR) gram-negative microorganisms in children?

The increasing incidence of infections caused by multidrug-resistant (MDR) or extremely drug-resistant (XDR) gram-negative organisms has led to the reemergence of colistin use. Clinical and demographic data were collected on 94 pediatric patients diagnosed with MDR or XDR gram-negative infections and treated with either a colistin-containing regimen (colistin group) or at least one antimicrobial agent other than colistin (noncolistin group). The overall clinical response rates were 65.8% in the colistin group and 70.0% in the noncolistin group (P = 0.33). The infection-related mortality rates were 11% in the colistin group and 13.3% in the noncolistin group (P = 0.74). There was no statistically significant difference in nephrotoxicity in the colistin and noncolistin groups. Colistin therapy was at least as effective and as safe as beta-lactam antibiotics or quinolones, with or without aminoglycosides, in the treatment of infections caused by gram-negative organisms and may be a therapeutic option in children.

The safety of polymyxin antibiotics

INTRODUCTION

The emergence of multidrug-resistant gram-negative bacteria has led to the increasing use of polymyxins. Nephrotoxicity and, to a lesser degree, neurotoxicity occur often during systemic polymyxin therapy. Scientific evidence regarding safety associated with polymyxins remains limited.

AREAS COVERED

Case reports/case series, observational studies and clinical trials assessing safety and toxicity of polymyxins were critically reviewed.

EXPERT OPINION

Polymyxins are drugs with a narrow therapeutic range. Nephrotoxicity is associated with both host factors and polymyxin exposure, and recent studies suggest that the relative risk of nephrotoxicity is similar for colistin and polymyxin B. Studies that have examined the safety of polymyxins have several limitations. Considering the available evidence, toxicities that may develop while on polymyxin therapy most often are mild to moderate in magnitude and reversible in nature. Strategies to minimize toxicity associated with polymyxins have evolved and include avoidance of toxic medications, careful dosing, use of critical care, therapeutic drug monitoring and development of polymyxin derivatives. However, given that polymyxin use has re-emerged in an era of increased antimicrobial resistance, the presence of other treatment modalities may be limited. Therefore, clinicians must consider overall risk to benefit ratio of continuing versus stopping polymyxin treatment and optimize minimization strategies to reduce polymyxin-induced toxicities.

Colistin-associated Acute Kidney Injury in Severely Ill Patients: A Step Toward a Better Renal Care? A Prospective Cohort Study

BACKGROUND

Critically ill patients with severe sepsis or septic shock may need relatively high colistin daily doses for efficacy against multidrug-resistant and extensively drug-resistant gram-negative rods. However, acute kidney injury (AKI) may represent a major dose-limiting adverse effect of colistin. We sought to determine AKI occurrence and to identify factors influencing AKI risk in severely ill patients receiving colistin according to a recently proposed dosing strategy.

METHODS

A prospective, observational, cohort study involving patients with severe sepsis or septic shock who received colistin was performed. AKI was defined according to Acute Kidney Injury Network criteria. Colistin administration was driven by a modified pharmacokinetics-pharmacodynamics (PK/PD)-based dosing approach.

RESULTS

Of 70 patients who received colistin at a median daily dose of 9 million IU (MIU; interquartile range, 5.87-11.1 MIU), 31 (44%) developed AKI. In univariate analysis, age, Acute Physiology and Chronic Health Evaluation (APACHE) II score, Sequential Organ Failure Assessment (SOFA), score and baseline renal impairment were significantly associated with AKI. Moreover, patients with AKI were less frequently treated with adjuvant ascorbic acid (P = .003). In multivariate analysis, independent predictors of AKI were baseline renal impairment (adjusted hazard ratio, 4.15; 95% confidence interval, 1.9-9.2; P < .001) and age (1.03; 1.0-1.05; P = .028), whereas a strong independent renal-protective role emerged for ascorbic acid (0.27; .12-.57; P < .001).

CONCLUSIONS

In severely ill patients receiving colistin according to a PK/PD-driven dosing approach, baseline renal impairment and older age strongly predict AKI occurrence, but concomitant administration of ascorbic acid markedly reduces AKI risk, allowing safer use of colistin.

Risk Factors for Colistin-Associated Acute Kidney Injury: A Multicenter Study from Turkey

The aim of this study was to investigate the incidence of acute kidney injury (AKI) and risk factors due to colistin use in patients infected with multidrug-resistant pathogens. This multicenter, retrospective, observational study was conducted in Turkey, at 5 different research and university hospitals. Cox regression analyses were performed, to determine independent predictors of AKI. From April 2012 to July 2014, a total of 216 patients aged between 18-94 years, treated with colistimethate sodium (CMS) were included in the study. The mean age of the patients was 60.3 ± 20.1 years. The overall incidence of AKI was 34.3% (74/216) at any time during treatment. Concomitant use of loop diuretics, baseline creatinine level, and CMS dosage were independently associated with AKI. According to our results, patients with higher baseline creatinine levels, or patients who had to use concomitant loop diuretics may need to be monitored more closely, and dose adjustment should be done promptly. More comprehensive studies are, however, still needed to evaluate the efficacy of low-dose colistin since higher doses tend to increase the risk of AKI.

The efficacy and nephrotoxicity associated with colistin use in an intensive care unit in Vietnam: Use of colistin in a population of lower body weight

BACKGROUND

There has been a growing need for colistin as a key drug for the treatment of MDR-GNB infection. Information on colistin use in Asian population is limited.

METHODS

A retrospective observational study was conducted to assess the efficacy and nephrotoxicity in critically ill adult patients who received intravenous colistin for MDR-GNB infection in the intensive care unit (ICU) at Bach Mai Hospital in Hanoi, Vietnam. Colistin was administered according to the dosing guideline that was based on pharmacokinetic, pharmacodynamic and toxicodynamic principles, adjusted by body weight and creatinine clearance.

RESULTS

Twenty-eight eligible patients were included. The mean patient age was 60±20.4 years. The mean body weight was 53±8.6kg. The mean daily dose of colistin was 4.1±1.6 MIU, and the mean cumulative dose of colistin was 48.2±22.8 MIU. Colistin therapies were classified as clinically effective in 19 (67.9%) cases. Six (21.4%) patients developed nephrotoxicity during the study period according to RIFLE criteria.

CONCLUSION

A personalized dosing protocol of colistin was effective, with low nephrotoxicity, among critically ill Vietnamese patients with low body weight. Further studies are warranted for assessing the efficacy and toxicity in a larger cohort.

High dose intravenous colistin methanesulfonate therapy is associated with high rates of nephrotoxicity; a prospective cohort study from Saudi Arabia

Background

Nephrotoxicity is an important adverse effect of colistin methanesulfonate (CMS) therapy. No data exist on rates and risk factors for colistin-related nephrotoxicity in Saudi Arabia (SA). We conducted a prospective cohort study to identify rates and risk factors for CMS nephrotoxicity in our patient population.

Methods

We prospectively included adult patients who received ≥48 hours of intravenous CMS therapy. Pregnant patients and those on renal replacement were excluded. Patients received 9 million units (mU) loading dose followed by 3 mU 8 hourly. In renal impairment, CMS dosing was adjusted according to calculated creatinine clearance (CrCl). Nephrotoxicity was defined as per RIFLE criteria (Risk, Injury, Failure, Loss and End-stage renal disease). Statistical analysis was performed using SPSS version 20.0 (IBM, Armonk, New York, USA). The study was approved by the institution’s Research Ethics Committee.

Results

A total of 67 patients were included in the study. Mean (±standard deviation) age was 57.5 (±24.0) years, Charlson Co-morbidity Score 2.88 (±2.39), CrCl 133.60 (±92.54) mL/min and serum albumin 28.65 (±4.45) g/L. Mean CMS dose was 0.11 (±0.04) mU/kg/day and mean total CMS dose received was 101.21 (±47.37) mU. Fifty-one (76.1%) patients developed RIFLE-defined nephrotoxicity. Mean total CMS dose and duration of therapy before onset of nephrotoxicity were 66.71 (±43.45) mU and 8.70 (±6.70) days, respectively. In bivariate analysis, patients with nephrotoxicity were significantly older (P 0.013) and had lower baseline serum albumin (P 0.008). Multivariate logistic regression identified serum albumin [odds ratio (OR) 0.72; 95% confidence interval (CI) 0.57–0.93; P 0.010] and intensive care admission (OR 16.38; 95% CI 1.37–195.55; P 0.027) as independent risk factors for CMS nephrotoxicity.

Conclusions

High dose intravenous CMS therapy is associated with high rates of nephrotoxicity in SA. Independent risk factors for colistin nephrotoxicity were baseline hypoalbuminemia and intensive care admission.

Colistin- and Polymyxin-Induced Nephrotoxicity

With the reintroduction of colistimethate and polymyxin B into clinical practice, a review of their individual and comparative nephrotoxicity attributes as reported in contemporary literature was undertaken. Given variability in definitions used for acute kidney injury, a particular focus was placed on studies utilizing the Risk-Injury-Failure-Loss-End Stage Kidney Disease (RIFLE) criteria of assessment to provide for standardized comparison. Primary risk factors examined included the influence of dosing and the receipt of concomitant nephrotoxins. The typical severity and time course of renal injury that develops were also analyzed. Nephrotoxicity rates with colistimethate appear to approach 50%, and could be of lower frequency and severity with polymyxin B based on limited literature. Acute kidney injury generally appears to be mild to moderate in magnitude and reversible in nature, though as many as 20% of patients experiencing it may require renal replacement therapy of some duration. The majority of studies showed some relationship with dosing- variably reported as being associated with daily dose or cumulative exposure. Traditional nephrotoxic agents did not appear to confer additional risk individually in the majority of investigations, though receipt of multiple concurrent nephrotoxins did yield a relationship in several. Further studies will be required to better characterize the renal adverse effect profile of these agents, particularly in the case of polymyxin B.

Validation of a model to predict the risk of nephrotoxicity in patients receiving colistin

Despite concerns about its nephrotoxicity, colistin often remains the only effective agent for treating multidrug-resistant Gram-negative infections. Published studies have reported a wide range of nephrotoxicity risk factors. To assess the clinical utility of various models, we compared their performances for predicting the risk of nephrotoxicity. We identified a model demonstrating reasonable overall risk assessment, with an observed/expected ratio of 1.29 (95% confidence interval [CI], 0.68 to 1.90) and a positive predictive value of 87.5% for identifying patients at high risk of developing nephrotoxicity.

Colistin nephrotoxicity increases with age

BACKGROUND

Colistin (COL) has become the backbone of the treatment of infections due to extensively drug-resistant (XDR) Gram-negative bacteria. The most common restriction to its use is acute kidney injury (AKI).

METHODS

We conducted a retrospective cohort study to evaluate risk factors for new-onset AKI in patients receiving COL. The cohort consisted of 198 adults admitted to 9 referral hospitals between January 2010 and October 2012 and treated with intravenous COL for ≥ 72 h. Patients with no pre-existing kidney dysfunction were compared in terms of risk factors and outcomes of AKI graded according to the RIFLE criteria. Logistic regression analysis was used to identify associated risk factors.

RESULTS

A total of 198 patients met the inclusion criteria, of whom 167 had no pre-existing kidney dysfunction; the mean patient age was 58.77 (± 18.98) y. Bloodstream infections (34.8%) and ventilator-associated pneumonia (32.3%) were the 2 most common indications for COL use. New-onset AKI developed in 46.1% of the patients, graded as risk (10%), injury (15%), and failure (21%). Patients with high Charlson co-morbidity index (CCI) scores (p = 0.001) and comparatively low initial glomerular filtration rate (GFR) estimations (p < 0.001) were more likely to develop AKI, but older age (p = 0.001; odds ratio 5.199, 95% confidence interval 2.684-10.072) was the major predictor in the multivariate analysis. In-hospital recovery from AKI occurred in 58.1%, within a median of 7 days.

CONCLUSIONS

COL-induced nephrotoxicity occurred significantly more often in patients older than 60 y of age and was related to low initial GFR estimations and high CCI scores, which were basically determined by age.