Predictors of serofast state after treatment for early syphilis in HIV-infected patients.

OBJECTIVES: Non-treponemal serological tests are used to monitor treatment response during syphilis infection. Syphilis- and HIV-coinfected patients may experience incomplete resolution in non-treponemal titres, which is referred to as the serofast state. The goal of this study was to evaluate risk factors for serofast state in HIV-infected patients. METHODS: From November 2015 to June 2018, 1530 HIV-positive patients were tested for syphilis using a Treponema pallidum particle agglutination (TPPA) assay. Among TPPA-positive patients, medical records were reviewed for early syphilis infection. Serofast state was defined as a less than four-fold decrease in non-treponemal antibody titres during a 6-month follow-up period in the absence of symptoms of syphilis. Baseline characteristics were tested as predictive factors of serological response. RESULTS: In all, 515 patients (33.7%) tested positive in TPPA assays, and in 163 patients at least one previous syphilis infection was documented. A total of 61 out of 163 patients (37.4%) were in a serofast state. A history of previous syphilis infection (61 vs. 43%; P = 0.04) was more common in serofast patients than in patients with serological cure after 6 months. Non-treponemal titres ≥ 1:32 before therapy (47 vs. 25%; P = 0.005) and adjunctive corticosteroids to prevent the Jarisch-Herxheimer reaction (35% vs 15%; P = 0.006) were associated with serological cure after 6 months, but corticosteroid therapy had no influence at 12 months. The intensity of syphilis treatment did not affect serological cure. CONCLUSION: Corticosteroids for prevention of the Jarisch-Herxheimer reaction were associated with earlier serological cure. Although serological response is the accredited surrogate method to monitor syphilis treatment, the biological significance of the serofast state remains unclear.

To prescribe, or not to prescribe: decision making in HIV-1 post-exposure prophylaxis.

OBJECTIVES: We investigated the trend in usage of post-exposure prophylaxis (PEP) after HIV-1 risk exposure and evaluated PEP prescription decision making of physicians according to guidelines. METHODS: All PEP consultations from January 2014 to December 2016 in patients presenting at the University Hospital of Cologne (Germany) were retrospectively analysed. HIV risk contacts included sexual and occupational exposure. The European AIDS Clinical Society (EACS) Guidelines for HIV PEP (version 9.0, 2017) were used for assessment. RESULTS: A total of 649 patients presented at the emergency department (ED) or the clinic for infectious diseases (IDC) for PEP consultations. A continuous increase in the number of PEP requests was recorded: 189 in 2014, 208 in 2015 and 252 in 2016. PEP consultations in men who have sex with men (MSM) showed a remarkable increase in 2016 (2014, n = 96; 2015, n = 101; 2016, n = 152). Decisions taken by physicians with a specialization in infectious diseases (n = 547) included 61 (11%) guideline-discordant prescriptions [2014: 14% (n = 22); 2015: 9% (n = 16); 2016: 11% (n = 23)]. Among these, sexual exposure accounted for 45 (74%) cases, including 15 cases of nonconsensual sex, while occupational exposure accounted for 14 (23%) cases and other exposure two cases (3%). The main reason for guideline-discordant PEP prescriptions was emotional stress of the patient (n = 37/61). CONCLUSIONS: PEP prescriptions are increasing and decision making is influenced by patients' emotional stress, but PEP prescriptions should be strictly administered according to risk assessment.

Higher rates of neuropsychiatric adverse events leading to dolutegravir discontinuation in women and older patients.

OBJECTIVES: Dolutegravir (DTG), a second-generation integrase strand transfer inhibitor (INSTI), is now among the most frequently used antiretroviral agents. However, recent reports have raised concerns about potential neurotoxicity. METHODS: We performed a retrospective analysis of a cohort of HIV-infected patients who had initiated an INSTI in two large German out-patient clinics between 2007 and 2016. We compared discontinuation rates because of adverse events (AEs) within 2 years of starting treatment with dolutegravir, raltegravir or elvitegravir/cobicistat. We also evaluated factors associated with dolutegravir discontinuation. RESULTS: A total of 1950 INSTI-based therapies were initiated in 1704 patients eligible for analysis within the observation period. The estimated rates of any AE and of neuropsychiatric AEs leading to discontinuation within 12 months were 7.6% and 5.6%, respectively, for dolutegravir (n = 985), 7.6% and 0.7%, respectively, for elvitegravir (n = 287), and 3.3% and 1.9%, respectively, for raltegravir (n = 678). Neuropsychiatric AEs leading to dolutegravir discontinuation were observed more frequently in women [hazard ratio (HR) 2.64; 95% confidence interval (CI) 1.23-5.65; P = 0.012], in patients older than 60 years (HR: 2.86; 95% CI: 1.42-5.77; P = 0.003) and in human leucocyte antigen (HLA)-B*5701-negative patients who initiated abacavir at the same time (HR: 2.42; 95% CI: 1.38-4.24; P = 0.002). CONCLUSIONS: In this large cohort, the rate of discontinuation of dolutegravir because of neuropsychiatric adverse events was significantly higher than for other INSTIs, at almost 6% within 12 months. Despite the limitations of this retrospective study, the almost three-fold higher discontinuation rates observed amongst women and older patients underscore the need for further investigation, especially in patient populations usually underrepresented in clinical trials.

Changes in the influence of lymphoma- and HIV-specific factors on outcomes in AIDS-related non-Hodgkin lymphoma.

BACKGROUND: We undertook the present analysis to examine the shifting influence of prognostic factors in HIV-positive patients diagnosed with aggressive non-Hodgkin lymphoma (NHL) over the last two decades. PATIENTS AND METHODS: We carried out a pooled analysis from an existing database of patients with AIDS-related lymphoma. Individual patient data had been obtained prior from prospective phase II or III clinical trials carried out between 1990 until 2010 in North America and Europe that studied chemo(immuno)therapy in HIV-positive patients diagnosed with AIDS-related lymphomas. Studies had been identified by a systematic review. We analyzed patient-level data for 1546 patients with AIDS-related lymphomas using logistic regression and Cox proportional hazard models to identify the association of patient-, lymphoma-, and HIV-specific variables with the outcomes complete response (CR), progression-free survival, and overall survival (OS) in different eras: pre-cART (1989-1995), early cART (1996-2000), recent cART (2001-2004), and contemporary cART era (2005-2010). RESULTS: Outcomes for patients with AIDS-related diffuse large B-cell lymphoma and Burkitt lymphoma improved significantly over time, irrespective of baseline CD4 count or age-adjusted International Prognostic Index (IPI) risk category. Two-year OS was best in the contemporary era: 67% and 75% compared with 24% and 37% in the pre-cART era (P < 0.001). While the age-adjusted IPI was a significant predictor of outcome in all time periods, the influence of other factors waxed and waned. Individual HIV-related factors such as low CD4 counts (<50/mm(3)) and prior history of AIDS were no longer associated with poor outcomes in the contemporary era. CONCLUSIONS: Our results demonstrate a significant improvement of CR rate and survival for all patients with AIDS-related lymphomas. Effective HIV-directed therapies reduce the impact of HIV-related prognostic factors on outcomes and allow curative antilymphoma therapy for the majority of patients with aggressive NHL.

Hodgkin lymphoma is as common as non-Hodgkin lymphoma in HIV-positive patients with sustained viral suppression and limited immune deficiency: a prospective cohort study.

OBJECTIVES: The incidence of HIV-related non-Hodgkin lymphoma (NHL) but not that of Hodgkin lymphoma (HL) has been declining. The aim of the study was to compare HIV-infected patients with NHL and HL with respect to antiretroviral therapy (ART) exposure at the time of lymphoma diagnosis. METHODS: HIV-infected patients with NHL and HL included in a prospective multicentre cohort study since January 2005 were compared with respect to ART exposure and viral load at the time of lymphoma diagnosis. RESULTS: As of 31 December 2012, data for 329 patients with NHL and 86 patients with HL from 31 participating centres were available. Patients with HL were more likely to be on ART (73.5% vs. 39.1%, respectively; P < 0.001) and more frequently had a viral load below the detection limit (57.3% vs. 27.9%, respectively; P < 0.001) than patients with NHL. The proportion of patients with HL was 8.0% in ART-naïve patients, 34.8% in patients with current HIV RNA < 50 HIV-1 RNA copies/mL, and 50.0% in patients with both HIV RNA < 50 copies/mL for > 12 months and a CD4 cell count of > 200 cells/µL. Of note, 45.8% of all patients with NHL were not currently on ART and had a CD4 count of < 350 cells/µL. CONCLUSIONS: This prospective cohort study shows that HL was as common as NHL in patients with sustained viral suppression and limited immune deficiency. In contrast to NHL, the majority of patients with HL were on effective ART, suggesting that ART provides insufficient protection from developing HL. The high proportion of untreated patients with NHL suggests missed opportunities for earlier initiation of ART.

Echocardiographic screening for pulmonary arterial hypertension in HIV-positive patients.

Human immunodeficiency virus (HIV) infection is associated with an increased risk for pulmonary arterial hypertension (PAH). Upon the screening of 220 asymptomatic HIV-positive individuals by echocardiography, we detected and confirmed HIV-associated PAH in 0.45 % of cases. Mild elevations of systolic pulmonary arterial pressure most probably owing to left ventricular diastolic dysfunction were found in 7.7 % of cases, without progress after 2 years. We suggest that the screening of asymptomatic HIV-positive patients for PAH should not be performed.

Causes of death in HIV-infected patients from the Cologne-Bonn cohort.

PURPOSE: Causes of death in human immunodeficiency virus (HIV)-infected subjects have changed in countries with high resources over the last several years. Acquired immunodeficiency syndrome (AIDS)-related diseases have become less prevalent, whereas deaths due to non-AIDS causes are increasing. The aim of the present study was to analyse causes of death in the Cologne-Bonn cohort. METHODS: Causes of death from the Cologne-Bonn cohort between 2004 and 2010 were systematically recorded using the CoDe algorithm (The Coding Causes of Death in HIV Project). RESULTS: In 3,165 patients followed from 2004 to 2010, 182 deaths occurred (5.7 %, 153 males, 29 females). The median age at the time of death was 47 years (range 24-85 years). The most frequent causes of death were AIDS-defining events (n = 60, 33 %), with non-Hodgkin lymphoma (NHL) (n = 29, 16 %) and infections (n = 20, 11 %) being the leading entities in this category. Non-AIDS malignancies accounted for 16 % (n = 29), non-HIV-related infections for 10 % (n = 18), cardiovascular diseases for 7 % (n = 14), suicide or accident for 4 % (n = 7) and liver diseases for 3 % (n = 5) of deaths (unknown n = 47, 26 %). Although the majority of patients (92.5 %) was on antiretroviral therapy (ART), only 50 % were virologically suppressed (HIV-RNA <50 copies/mL) and 44 % had a decreased CD4+ count (<200/µL) at their last visit before death. CONCLUSION: One-third of the causes of death in our cohort between 2004 and 2010 was AIDS-related. Since most of these deaths occur with severe immune suppression, they can possibly be prevented by the early diagnosis and treatment of HIV infection. Care providers must be aware of an increased risk for a broad range of diseases in HIV-infected patients and should apply appropriate preventive measures.

Clinical course and quality of care in ART-naïve patients newly presenting in a HIV outpatient clinic.

OBJECTIVES: Little data exist about the quality of care for HIV-infected subjects in Germany. We investigated the clinical course of HIV-infected subjects newly presenting in our HIV outpatient clinic. METHODS: Antiretroviral therapy (ART)-naïve HIV-infected subjects presenting between 2007 and 2008 were followed until June 2012. Clinical data and laboratory parameters were collected prospectively and analysed retrospectively. RESULTS: From 281 subjects included, 34 patients (12%) were lost to follow-up. 247 subjects remained, and 171 patients were followed for 1,497 days [1,121/1,726] (all data: median [interquartile range]). ART was started in 199 patients (81%) 182 days [44/849] after HIV diagnosis, and all patients were treated according to European guidelines or within clinical trials. The CD4 cell count at first presentation was 320/µL [160/500] and declined to 210/µL [100/300] at ART start. 12 months thereafter, the CD4 cell count increased to 410/µL [230/545]. The HIV RNA was suppressed below 50 copies/mL after 108 days [63/173] in 182 patients (91%). Initial ART was changed in 71 patients (36%) after 281 days [99/718], in five patients (7%) due to virological failure, in 66 patients (93%) due to other reasons, e.g. side effects or patient's request. CONCLUSION: Two-thirds of the included patients were followed for more than 3 years, and ART was initiated in 81% of the patients leading to complete virological suppression in most patients. Compliance of physicians with treatment guidelines was high. Late presentation with a severely compromised immune function remains a problem and impairs the otherwise good prognosis of HIV infection.

Evaluation of an infectious disease consultation programme in a German tertiary care hospital.

PURPOSE: To evaluate a newly implemented infectious disease (ID) consultation service in terms of patient care, outcome and antibiotic prescription and to describe factors influencing adherence to recommendations. METHODS: Data from consultations during the first 6 months of the ID consultation program were collected and evaluated. Consultation requests, diagnostic results, treatment outcomes and antibiotic recommendations were categorised. Diagnostic and therapeutic recommendations were assessed and rated for adherence and outcome. Statistical analysis was performed to identify factors influencing adherence and treatment outcome. RESULTS: A total of 251 consultations were assessed. In most cases, ID specialists were asked for further advice regarding a previously initiated anti-infective treatment (N = 131, 52 %). In 54 of 195 (28 %) first consultations, the ID specialist proposed a differential diagnosis that differed from that of the working diagnoses submitted with the consultation request, and which was subsequently confirmed in 80 % of these cases. Diagnostic and therapeutic recommendations were made in 190 (76 %) and 240 (96 %) of the consultations, respectively. A change in the current treatment was recommended in 66 % of consultations; 37 % of recommendations were cost-saving and 26 % were cost-neutral. Compliance with diagnostic and therapeutic recommendations was rated as good by pre-specified criteria in 65 and 86 % of consultations, respectively. Treatment outcome was correlated with adherence to diagnostic recommendations (P = 0.012). Twenty-nine patients (16 %) died during the same hospital stay. CONCLUSION: Infectious disease consultations may help to establish the correct diagnosis, resulting in the appropriate treatment being provided to a severely sick patient population. Treatment outcome was improved in cases of good diagnostic adherence to the recommendations of the ID specialist.

Therapy and prophylaxis of opportunistic infections in HIV-infected patients: a guideline by the German and Austrian AIDS societies (DAIG/ÖAG) (AWMF 055/066).

INTRODUCTION: There was a growing need for practical guidelines for the most common OIs in Germany and Austria under consideration of the local epidemiological conditions. MATERIALS AND METHODS: The German and Austrian AIDS societies developed these guidelines between March 2010 and November 2011. A structured Medline research was performed for 12 diseases, namely Immune reconstitution inflammatory syndrome, Pneumocystis jiroveci pneumonia, cerebral toxoplasmosis, cytomegalovirus manifestations, candidiasis, herpes simplex virus infections, varizella zoster virus infections, progressive multifocal leucencephalopathy, cryptosporidiosis, cryptococcosis, nontuberculosis mycobacteria infections and tuberculosis. Due to the lack of evidence by randomized controlled trials, part of the guidelines reflects expert opinions. The German version was accepted by the German and Austrian AIDS Societies and was previously published by the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF; German Association of the Scientific Medical Societies). CONCLUSION: The review presented here is a translation of a short version of the German-Austrian Guidelines of opportunistic infections in HIV patients. These guidelines are well-accepted in a clinical setting in both Germany and Austria. They lead to a similar treatment of a heterogeneous group of patients in these countries.

Liver involvement in HIV-infected patients diagnosed with syphilis.

PURPOSE: Liver involvement in syphilis has been studied in cohorts of human immunodeficiency virus (HIV)-negative individuals despite the scarcity of data on such HIV-infected patients. Th aim of this study was to assess hepatic involvement of HIV-infected patients diagnosed with syphilis. METHODS: Patients with syphilis and liver involvement, including all stages of syphilis, were systematically identified in our HIV cohort between 2004 and 2008. RESULTS: Of the 1,599 HIV-infected patients identified during the study period, 100 were diagnosed with acute syphilis, all of whom were male. Of these 100 patients, 84% were men who have sex with men. Laboratory parameters of liver involvement were present in 19 of the 100 HIV-infected patients with syphilis; these resolved after successful antibiotic treatment. Among these 19 patients, six were diagnosed to be in the latent stage, with elevated liver enzymes and parameters of inflammation representing the only distinctive feature. CONCLUSIONS: Based on our results, syphilis should be included in the differential diagnosis of increased liver enzymes in HIV-infected patients.

Acceptance and tolerability of an adjuvanted nH1N1 vaccine in HIV-infected patients in the Cologne-Bonn cohort.

OBJECTIVE: To evaluate the acceptance and tolerability of the nH1N1 2009 vaccine in HIV-positive individuals. METHOD: 758 patients were included in this prospective study. Different study populations were formed: The Tolerability Study Group consists of HIV-infected patients who visited three outpatient clinics (Cologne, Bonn, Freiburg) during a predefined time period. Patients were offered nH1N1 vaccination. Those accepting were administered a standard dose AS03 adjuvant nH1N1 vaccine. Questionnaires to report side effects occurring within 7 days after immunization were handed out. In a substudy conducted during the same time period, acceptance towards immunization was recorded. This Acceptance Study Group consists of all HIV-infected patients visiting the Cologne clinic. They were offered vaccination. In case of refusal, motivation was recorded. RESULTS: In the Tolerability Study Group, a total of 475 patient diaries returned in the three study centres could be evaluated, 119 of those (25%) reported no side effects. Distribution of symptoms was as follows: Pain 285/475 patients (60%), swelling 96 (20%), redness 54 (11%), fever 48/475 (10%), muscle/joint ache 173 (36%), headache 127 (27%), and fatigue 210 (44%). Association of side effects with clinical data was calculated for patients in Cologne and Bonn. Incidence of side effects was significantly associated with CDC stages A, B compared to C, and with a detectable viral load (>50 copies/mL). No correlation was noted for CD4 cell count, age, gender or ethnicity. - In the Acceptance Study Group, 538 HIV-infected patients were offered vaccination, 402 (75%) accepted, while 136 (25%) rejected. Main reasons for rejection were: Negative media coverage (35%), indecisiveness with preference to wait until a later date (23%), influenza not seen as personal threat (19%) and scepticism towards immunization in general (10%). CONCLUSION: A total of 622 HIV-infected patients were vaccinated against nH1N1-influenza in the three study centres. No severe adverse events were reported. The tolerability was in most parts comparable to general population. Acceptance rate towards influenza vaccination was high (75%). Those refusing the immunization mentioned negative media coverage as the major influence on their decision.

Long-term remission in progressive multifocal leukoencephalopathy caused by idiopathic CD4+ T lymphocytopenia: a case report.

Progressive multifocal leukoencephalopathy is caused by JC virus, an opportunistic infection of the central nervous system. Antiretroviral treatment for progressive multifocal leukoencephalopathy in human immunodeficiency virus-infected patients is beneficial, but few data exist for patients who are not infected with human immunodeficiency virus. Idiopathic CD4+ T lymphocytopenia excludes human immunodeficiency virus infection. We describe a patient with progressive multifocal leukoencephalopathy with underlying idiopathic CD4+ T lymphocytopenia in whom functional recovery occurred without antiviral therapy.

AIDS-related progressive multifocal leukoencephalopathy in the era of HAART: report of two cases and review of the literature.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system. It is caused by the JC virus (JCV), a human polyomavirus replicating in human glial cells. PML is the result of the reactivation of latent JCV infection that usually occurs in the setting of cellular immunodeficiencies such as HIV-1 infection. Epidemiologic data suggest that the impact of highly active antiretroviral therapy (HAART) on the incidence of PML is less profound than seen with other opportunistic infections. Given the lack of an effective and specific therapy for PML, HAART remains the only therapeutic option in patients with PML. However, a significant number of cases appear unresponsive to antiretroviral therapy. Moreover, there is growing data on unexpected inflammatory cases of PML after initiation of HAART. Thus, PML will remain a relevant cause of morbidity and mortality in HIV- 1-infected patients. Here we report two cases of PML, along with a concise review of the literature on this important disease.

Acute effects of ACE inhibition on coronary endothelial dysfunction.

The prerequisite of atherosclerosis, endothelial dysfunction, is characterised by impaired endothelium-dependent vasodilation caused by the reduced bioavailibility of nitric oxide (NO). In order to assess the role of acute ACE inhibition in this setting, coronary arterial endothelial function was quantified following acute intracoronary administration of the angiotensin-converting enzyme (ACE) inhibitor quinapril. Twenty-one patients with non-limiting coronary artery disease were studied before and after acute intracoronary administration of 10 mg quinapril. Nine patients received pre-treatment with the angiotensin AT(1)-receptor antagonist losartan (2 x 50 mg, p.o.). Coronary cross-sectional diameter was measured via quantitative angiography and microvascular reaction was investigated by intracoronary Doppler flow measurement during intracoronary infusion of 0.1 to 10 micromol/l acetylcholine. Quinapril acutely improved endothelial dysfunction on the macro- as well as the microvascular level. Losartan did not alter macrovascular function but facilitated microvascular endothelial function. Acute quinapril application led to no further improvement of endothelial dysfunction in patients pre-treated with losartan. Acute quinapril infusion improved endothelial function in patients with coronary heart disease. Treatment with the AT(1)-receptor antagonist losartan led to a slight improvement in microvascular endothelial function, but pre-treatment with losartan blunted the vascular effect of quinapril, suggesting that the combination of ACE inhibition and AT(1)-receptor antagonism may not exert a synergistic benefical impact on the coronary vasculature.

Superior virological efficacy of ritonavir-boosted protease inhibitor regimens compared to single protease inhibitor therapy.

Low dose-ritonavir boosted protease inhibitors are increasingly being used for the first-line antiretroviral treatment, though their virological efficacy has just poorly been compared to alternative antiretroviral therapies. Here, we retrospectively investigated the virological responses of 316 protease inhibitor-naive HIV patients receiving highly active antiretroviral treatment based on a single (n = 256) or a ritonavir-boosted protease inhibitor (n = 60), both in the background of two nucleoside analogues. - By intent-to-treat analysis, a complete initial virological response was achieved in 71.8% of all patients in the single protease inhibitor group (indinavir: 76%, ritonavir: 67.5%, nelfinavir: 70.6%) and in 88.3% (p = 0.008) of patients treated with a boosted protease inhibitor (saquinavir/r: 71.4%, indinavir/r: 92.1%, lopinavir/r: 86.6%). The multivariate risk analysis identified boosted PI treatment as an independent predictor of a complete virological response (OR = 2.8, p=0.02). Viral rebound after an initial complete virological response was observed in 28% and 17% (p = 0.06) of patients receiving a single or a dual protease inhibitor, respectively. The rate of durable viral suppression over 12 months was 44.5% and 56.7% (p = 0.09) in the respective study cohorts. Ritonavir-boosted protease inhibitors therefore seem to induce a superior virological response rate and a higher degree of sustained virological suppression.

Pharmacokinetic and pharmacodynamic analysis of efavirenz dose reduction using an in vitro-in vivo extrapolation model.

The pharmacokinetics (PK) of efavirenz (EFV) is characterized by marked interpatient variability that correlates with its pharmacodynamics (PD). In vitro-in vivo extrapolation (IVIVE) is a "bottom-up" approach that combines drug data with system information to predict PK and PD. The aim of this study was to simulate EFV PK and PD after dose reductions. At the standard dose, the simulated probability was 80% for viral suppression and 28% for central nervous system (CNS) toxicity. After a dose reduction to 400 mg, the probabilities of viral suppression were reduced to 69, 75, and 82%, and those of CNS toxicity were 21, 24, and 29% for the 516 GG, 516 GT, and 516 TT genotypes, respectively. With reduction of the dose to 200 mg, the probabilities of viral suppression decreased to 54, 62, and 72% and those of CNS toxicity decreased to 13, 18, and 20% for the 516 GG, 516 GT, and 516 TT genotypes, respectively. These findings indicate how dose reductions might be applied in patients with favorable genetic characteristics.

Effect of an antiretroviral regimen containing ritonavir boosted lopinavir on intestinal and hepatic CYP3A, CYP2D6 and P-glycoprotein in HIV-infected patients.

This study aimed to quantify the inhibition of cytochrome P450 (CYP3A), CYP2D6, and P-glycoprotein in human immunodeficiency virus (HIV)-infected patients receiving an antiretroviral therapy (ART) containing ritonavir boosted lopinavir, and to identify factors influencing ritonavir and lopinavir pharmacokinetics. We measured activities of CYP3A, CYP2D6, and P-glycoprotein in 28 patients before and during ART using a cocktail phenotyping approach. Activities, demographics, and genetic polymorphisms in CYP3A, CYP2D6, and P-glycoprotein were tested as covariates. Oral midazolam clearance (overall CYP3A activity) decreased to 0.19-fold (90% confidence interval (CI), 0.15-0.23), hepatic midazolam clearance and intestinal midazolam availability changed to 0.24-fold (0.20-0.29) and 1.12-fold (1.00-1.26), respectively. In CYP2D6 extensive metabolizers, the plasma ratio AUC(dextromethorphan)/AUC(dextrorphan) increased to 2.92-fold (2.31-3.69). Digoxin area under the curve (AUC)(0-12) (P-glycoprotein activity) increased to 1.81-fold (1.56-2.09). Covariates had no major influence on lopinavir and ritonavir pharmacokinetics. In conclusion, CYP3A, CYP2D6, and P-glycoprotein are profoundly inhibited in patients receiving ritonavir boosted lopinavir. The covariates investigated are not useful for a priori dose selection.