Time In HIV-infected Patients Research Articles

How estimating nuisance parameters can reduce the variance (with consistent variance estimation).

We often estimate a parameter of interest when the identifying conditions involve a finite-dimensional nuisance parameter . Examples from causal inference are inverse probability weighting, marginal structural models and structural nested models, which all lead to unbiased estimating equations. This article presents a consistent sandwich estimator for the variance of estimators that solve unbiased estimating equations including which is also estimated by solving unbiased estimating equations. This article presents four additional results for settings where solves (partial) score equations and does not depend on . This includes many causal inference settings where describes the treatment probabilities, missing data settings where describes the missingness probabilities, and measurement error settings where describes the error distribution. These four additional results are: (1) Counter-intuitively, the asymptotic variance of is typically smaller when is estimated. (2) If estimating is ignored, the sandwich estimator for the variance of is conservative. (3) A consistent sandwich estimator for the variance of . (4) If with the true plugged in is efficient, the asymptotic variance of does not depend on whether is estimated. To illustrate we use observational data to calculate confidence intervals for (1) the effect of cazavi versus colistin on bacterial infections and (2) how the effect of antiretroviral treatment depends on its initiation time in HIV-infected patients.

Vitamin D in Human Immunodeficiency Virus Infection: Influence on Immunity and Disease.

People living with human immunodeficiency virus (HIV) infection typically have hypovitaminosis D, which is linked to a large number of pathologies, including immune disorders and infectious diseases. Vitamin D (VitD) is a key regulator of host defense against infections by activating genes and pathways that enhance innate and adaptive immunity. VitD mediates its biological effects by binding to the Vitamin D receptor (VDR), and activating and regulating multiple cellular pathways. Single nucleotide polymorphisms in genes from those pathways have been associated with protection from HIV-1 infection. High levels of VitD and VDR expression are also associated with natural resistance to HIV-1 infection. Conversely, VitD deficiency is linked to more inflammation and immune activation, low peripheral blood CD4+ T-cells, faster progression of HIV disease, and shorter survival time in HIV-infected patients. VitD supplementation and restoration to normal values in HIV-infected patients may improve immunologic recovery during combination antiretroviral therapy, reduce levels of inflammation and immune activation, and increase immunity against pathogens. Additionally, VitD may protect against the development of immune reconstitution inflammatory syndrome events, pulmonary tuberculosis, and mortality among HIV-infected patients. In summary, this review suggests that VitD deficiency may contribute to the pathogenesis of HIV infection. Also, VitD supplementation seems to reverse some alterations of the immune system, supporting the use of VitD supplementation as prophylaxis, especially in individuals with more severe VitD deficiency.

Changes in liver steatosis evaluated by transient elastography with the controlled attenuation parameter in HIV-infected patients.

There are scant data on the progression of hepatic steatosis (HS) in HIV infection. We therefore evaluated changes in HS over time in HIV-infected patients using the controlled attenuation parameter (CAP). A prospective cohort of 326 HIV-infected patients was included in this study. All patients underwent a CAP measurement. Changes in steatosis were evaluated by calculating the median (Q1-Q3) difference between baseline and 12-month CAP values. The median (Q1-Q3) CAP was 221 (196-252) dB/m at baseline and 224 (198-257) dB/m at the 12-month visit (P = 0.617). Significant steatosis, that is, CAP ≥ 238 dB/m, was observed in 76 individuals (37%) at baseline and in 80 (39%) at the 12-month visit (P = 0.683). The following variables were associated with ΔCAP: plasma HIV RNA [< 50 vs. ≥ 50 HIV-1 RNA copies/mL: median (Q1-Q3) ΔCAP, 4 (-21, 27) vs. -21 (-49, 4) dB/m, respectively; P = 0.024]; body mass index (BMI) [no increase vs. increase: -13 (-40, 4) vs. 14 (-6, 32) dB/m, respectively; P < 0.001]; triglycerides [no increase vs. increase: -1 (-30, 22) vs. 15 (-3, 40) dB/m, respectively; P = 0.001]; fasting plasma glucose [not impaired vs. impaired: -4 (-31, 16) vs. 30 (15, 49) dB/m, respectively; P < 0.001]; and raltegravir [no vs. yes: 5 (-20, 29) vs. -11 (-37.5, 15) dB/m, respectively; P = 0.018]. The only factor independently associated with ΔCAP was BMI [B (standard error): 9.03 (1.9); P < 0.001]. Increases in CAP values over a period of 12 months in HIV-infected patients were strongly associated with elevations in BMI. Other metabolic factors and antiretroviral drugs were not predictors of CAP changes independent of BMI.

Increased homocysteine plasma level is associated with shortened prothrombin time in HIV-infected patients

Objective: To find factors associated with increased homocysteine plasma level in HIV-infected patients.Methods: Cross-sectional study, carried out as a supplementary task to the standard care of HIV-infected patients. The possible association of increased homocysteine plasma level with blood analyses results was assessed with a multiple linear regression analysis, using the automatic linear modeling available in SPSS version 22.Results: A total of 145 patients were included. Creatinine was higher than normal in 7 patients (5%), prothrombin time was shortened in 36 patients (25%), and a monoclonal gammopathy was detected in 2 patients (1%). In the regression analysis, an association was found between high homocysteine plasma level and the following variables: low prothrombin time (β coefficient −0.286, confidence interval −1.1854 to −0.754, p < 0.001), high creatinine (coefficient 9.926, confidence interval 6.351–15.246, p < 0.001), low folic acid (coefficient −0.331, confidence interval −0–483 to −0.187, p < 0.001), and low vitamin B12 (coefficient −0.007, confidence interval −0.01 to −0.001, p = 0.005).Conclusion: An association was found between increased homocysteine plasma level and shortened prothrombin time.

Decline in locomotor functions over time in HIV-infected patients

To assess changes in locomotor function in HIV-infected patients and to evaluate the determinants of variations in lower limb muscle performance. Longitudinal study within the ANRS CO3 Aquitaine Cohort. Standardized locomotor tests, including global functional capacity [6-min walk distance (6MWD)] and lower limb muscle performance tests [five times sit-to-stand (5STS) test], were performed in HIV-infected adults at baseline and 2-year follow-up. Evolution of performances and determinants of 5STS time were studied in linear mixed-effects models. At baseline (354 patients, 90% on antiretroviral treatment), median 5STS time was 9.8 s and 6MWD 549 m. Poorer performances were associated with falls, reported by 12% of 178 patients at follow-up. Estimated mean deterioration was +0.24 s/year (P < 10) for 5STS time and -11 m/year (P < 10) for 6MWD. In multivariable analyses, older age was associated with worse baseline 5STS time (+0.47 s/10-year age increase; P = 10), but not with further deterioration. Deterioration was greater in prior injecting drug users compared to others (difference in slope +0.62 s/year; P = 0.04). 5STS time at any time point was worse in patients with history of cerebral AIDS conditions (+2.47 s; P < 10) and diabetes (+0.95 s; P = 0.02) than in others. No significant associations were found for antiretroviral treatment type, viral load or CD4 cell count. Compared to published data from healthy persons of similar age, baseline 5STS time and 6MWD were poorer in HIV-infected adults and associated with subsequent falls. Test performances deteriorated further over time. Age, diabetes, neurologic complications and injection drug use, rather than virologic factors, contribute to variations in lower limb muscle performance.

Protein intake is associated with HIV disease progression in HIV‐infected patients (810.9)

Background: This longitudinal study examines the effect of protein intake on markers of HIV disease progression.Methods: In a secondary analysis of data from 267 HIV+ patients on ART over a period of 6 months, we estimated protein intake from 24‐hour recalls and obtained CD4 cell counts and viral load from medical records. Multiple Linear Regressions and Mixed Models were used for over time analyses. Statistical significance was set at p&lt;0.05.Results: Participants mean age was 49±5 years, 62% were male and 71.3% were African Americans. Mean protein intake was 111±87 g/day (1.8 times the RDA for age and gender), mean CD4 cell count was 516.7±342 cells/μL and viral load 2.5±1.5 log10. Protein intake (g/day) was associated with decreased CD4 cell counts (β=‐0.68, p=0.05) and increased viral loads (β=51.27, p&lt;0.01) over time. This adverse relationship remained significant (β=44.4, p&lt;0.01), after adjusting for age and gender.Conclusion: The results suggest a detrimental relationship of excessive protein consumption with disease progression over time in HIV‐infected patients on ART.Grant Funding Source: NIDA

Mitochondrial Evolution in HIV-Infected Children Receiving First- or Second-Generation Nucleoside Analogues

Highly active antiretroviral therapy (HAART) and HIV-related mitochondrial toxicity lead to several adverse effects and have become a major issue, especially in children. The main goal in the treatment of HIV-infected children is to maximize cost-effectiveness while minimizing toxicity. We aimed to study the evolution of mitochondrial parameters over time in children receiving different types antiretroviral regimens. We followed-up 28 HIV-infected children receiving HAART including either first-generation nucleoside reverse transcriptase inhibitors (1gNRTIs; didanosine, zidovudine, or stavudine; n = 15) or second-generation NRTIs (2gNRTIs; the remaining drugs; n = 13) for a period of 2 years for their immunovirological and mitochondrial status, and compared these subjects with a group of untreated HIV-infected patients (n = 10) and uninfected controls (n = 27). We measured T-lymphocyte CD4+ content (flow cytometry), viral load (real-time polymerase chain reaction), and lactate levels (spectrophotometry); we assessed mtDNA content (real-time polymerase chain reaction), mitochondrial protein levels (Western blot), oxidative stress, mitochondrial mass, and electron transport chain function (spectrophotometry) in peripheral blood mononuclear cells. At the second time point, lactate levels were significantly higher in children on 1gNRTIs compared with those receiving 2gNRTIs (1.28 ± 0.08 vs. 1.00 ± 0.07 mmol/L, respectively; P = 0.022). MtDNA content was similar among all HIV-infected groups and significantly lower than in healthy controls at baseline. Oxidative stress tended to increase over time in all the groups, with no differences among them. However, a significant decrease in cytochrome c oxidase activity was found over time in HIV-infected patients; this decline was greater in the 1gNRTIs group. HIV infection and the use of 1gNRTIs caused greater mitochondrial damage than 2gNRTIs over time. The higher lactate levels and the significant decrease observed in cytochrome c oxidase activity argue against the use of 1gNRTIs in HIV-infected children when an alternative is available, in accordance with international recommendations.

A dynamic Bayesian nonlinear mixed-effects model of HIV response incorporating medication adherence, drug resistance and covariates

HIV dynamic studies have contributed significantly to the understanding of HIV pathogenesis and antiviral treatment strategies for AIDS patients. Establishing the relationship of virologic responses with clinical factors and covariates during long-term antiretroviral (ARV) therapy is important to the development of effective treatments. Medication adherence is an important predictor of the effectiveness of ARV treatment, but an appropriate determinant of adherence rate based on medication event monitoring system (MEMS) data is critical to predict virologic outcomes. The primary objective of this paper is to investigate the effects of a number of summary determinants of MEMS adherence rates on virologic response measured repeatedly over time in HIV-infected patients. We developed a mechanism-based differential equation model with consideration of drug adherence, interacted by virus susceptibility to drug and baseline characteristics, to characterize the long-term virologic responses after initiation of therapy. This model fully integrates viral load, MEMS adherence, drug resistance and baseline covariates into the data analysis. In this study we employed the proposed model and associated Bayesian nonlinear mixed-effects modeling approach to assess how to efficiently use the MEMS adherence data for prediction of virologic response, and to evaluate the predicting power of each summary metric of the MEMS adherence rates. In particular, we intend to address the questions: (i) how to summarize the MEMS adherence data for efficient prediction of virologic response after accounting for potential confounding factors such as drug resistance and covariates, and (ii) how to evaluate treatment effect of baseline characteristics interacted with adherence and other clinical factors. The approach is applied to an AIDS clinical trial involving 31 patients who had available data as required for the proposed model. Results demonstrate that the appropriate determinants of MEMS adherence rates are important in order to more efficiently predict virologic response, and investigations of adherence to ARV treatment would benefit from measuring not only adherence rate but also its summary metric assessment. Our study also shows that the mechanism-based dynamic model is powerful and effective to establish a relationship of virologic responses with medication adherence, virus resistance to drug and baseline covariates.

The evolving burden of HIV infection compared with other chronic diseases in northern Italy*

The aim of the study was to estimate the burden and direct costs of diseases in HIV-infected patients (either opportunistic illnesses or other chronic diseases) with respect to the HIV-uninfected population. These estimates will be useful for the projection of future direct costs of HIV care. A population-based study was conducted in the Brescia Local Health Agency in northern Italy. An administrative database recorded diagnoses, deaths, drug prescriptions and health resource utilization for all medical and surgical patients in the region from 2003 to 2007. The study estimated the prevalence of HIV infection as well as HIV-related mortality and annual cost per patient, and compared mortality and costs related to HIV infection with those for a set of 15 other chronic diseases. The standardized hazard ratio (SHR) and standardized mortality ratio (SMR) were obtained using an indirect standardization method. The prevalence of HIV infection increased from 218 per 100,000 inhabitants in 2003 to 263 per 100,000 in 2007. Although mortality rates decreased markedly (from 24 per 1000 HIV-infected patients in 2003 to 16 per 1000 in 2007), the data show that mortality was still higher in HIV-infected patients compared with the general population in the most recent years (SMR 8.8 in 2007). In each year included in the study, HIV-infected patients had higher rates of care-seeking for chronic diseases, including liver diseases (SHR>8), neuropathy, oesophagus-gastro-duodenum diseases, serious psychiatric disorders and renal failure (SHR approximately 3 for each). Also, the rate of medical attendance for neoplasias, chronic pulmonary disease, diabetes, and cardiovascular disease increased over time in HIV-infected patients compared with the general population. Ranking diseases in order of their total cost to the health system, HIV infection ranked 12th, with total costs of €28.6 million in 2007. Ranking in order of cost per patient, HIV infection ranked third, with a cost per patient of €9894 in 2007. HIV-infected patients with concomitant chronic diseases had higher average costs. The cost per patient in 2007 was €8104 for HIV-infected patients without other chronic diseases, €9908 for HIV infection plus cardiovascular disease, €11,370 for HIV infection plus chronic liver disease and €12,013 for HIV infection plus neoplasias. The prevalence and population cost of people living with HIV are likely to increase as a result of prolonged survival, aging of HIV-infected patients and increased risk of other chronic diseases. In the near future, HIV infection will rank as one of the most costly chronic diseases. Prevention strategies need to be more widely adopted to control the growing burden of the HIV epidemic and other chronic diseases affecting HIV-infected patients.

Cancer in cohort of HIV-infected population: prevalence and clinical characteristics

To determine the incidence and survival time of acquired immunodeficiency syndrome-related malignancies among HIV-infected population. A clinical database search, chart review and verification with health records were undertaken for all AIDS-defining cancers diagnosed in Zhongnan Hospital Wuhan University, Hubei Province, China. Kaplan-Meier method was used to evaluate survival time in HIV-infected patients with cancer. A total of 3,554 patients with 11,072 person-years of HIV follow-up care were reviewed from January 2004 to December 2008. Sixty-three cancer cases were identified. The median ages of HIV-positive cancer cases were 42.4 ± 8.8 years, CD4 count were 220.9 ± 142.3/µl. The common cancers were non-Hodgkin's lymphoma (NHL, 28.6%), cervical cancer (22.2%), liver cancer (17.5%). Statistically significantly elevated SIRs were observed in NHL (SIR in all = 34.5, 95% CI 11.7-89.9, SIR in males = 45.3, 95% CI 24.7-138.9, females = 12.2, 95% CI 3.9-38.2), invasive cervical cancer (SIR = 68.1, 95% CI 19.2-84.5), liver cancer (SIR = 6.0, 95% CI 2.6-12.2), nasopharyngeal cancer (SIR = 6.2, 95% CI 1.5-44.9), bladder cancer (SIR = 4.9, 95% CI 0.9-22.9), esophageal cancer (SIR = 3.1, 95% CI 0.7-14.3), and stomach cancer (SIR = 2.6, 95% CI 0.6-11.6). All cancers combined showed a statistically significantly elevated SIR of 4.1 (95% CI 2.5-4.6), SIR for all cancers was much higher in female (SIR = 4.8, 95% CI 3.2-7.3) than in male (SIR = 3.1, 95% CI 2.1-4.3). Among HIV-positive patients with cancer, the median survival time was 14.5 ± 3.8 months in NHL group, 28.9 ± 3.6 months in cervix group, 5.1 ± 1.1 months in liver group, and 26.7 ± 6.7 months in other groups. The median survival time in HIV-infected group (23.1 ± 3.5 months) was shorter than that in non-HIV-infected group (43.0 ± 5.1 months), (P < 0.05). NHL, cervical cancers and liver cancer are common cancers among HIV-infected individuals in Hubei, China. Most malignant diseases that arise in the setting of HIV infection tend to occur at a more advanced stage with shorter survival time.

Highly Sensitive C-Reactive Protein, Body Mass Index, and Serum Lipids in HIV-Infected Persons Receiving Antiretroviral Therapy: A Longitudinal Study

Antiretroviral therapy (ART) affects cardiovascular disease (CVD) risk. In the general population, highly sensitive creactive protein (hsCRP) is an established predictor of future coronary events. Little is known about its utility in chronic inflammatory conditions such as HIV infection. We assessed relationships between hsCRP and metabolic parameters over time in HIV-infected patients on ART. Data are from a prospective cohort of HIV-infected adults enrolled June 2005 to July 2007. Participants were receiving ART, had HIV-1 RNA,10,000 copies per milliliter, and no diabetes or CVD. Nonlinear mixed-effect regression models assessed relationships between body mass index (BMI), lipids, and hsCRP over time adjusting for covariates. Ninety-four individuals had data from $1 study visit. Median age was 44 years, 27% were female, 57% white, and 54% were on protease inhibitors. Median CD4+ T cells, HIV-1 RNA, and hsCRP were 502 cells per cubic millimeter, 50 copies per milliliter, and 2.94 mg/dL, respectively. Median Framingham score was 3. Multivariate analysis identified associations between increased hsCRP and greater BMI (P = 0.001), higher non-high-density lipoprotein cholesterol (P = 0.013) and triglycerides (P = 0.017), and lower high-density lipoprotein cholesterol (P = 0.015). Among HIV-infected adults with low estimated CVD risk and virologic suppression on ART, hsCRP was elevated and independently associated with BMI and lipid changes. Future studies should assess associations between hsCRP and clinical outcomes.

Incidence and causes of death in HIV‐infected persons receiving highly active antiretroviral therapy compared with estimates for the general population of similar age and from the same geographical area

Since the introduction of highly active antiretroviral therapy (HAART), the incidence of death in HIV-infected patients has dramatically decreased, and causes of death other than those related to HIV infection have increased, although it is unclear how these parameters compare with those in the age-matched general population living in the same geographical region. Consecutive HIV-infected adults who were prescribed HAART in our hospital were prospectively followed from January 1997 to December 2004 or until death, loss to follow-up or discontinuation of HAART. Estimations of the annual incidence and causes of death in the general population of similar age in Catalonia per calendar year in the study period were obtained and compared with those in the HIV-infected cohort. There were 235 deaths among the 4471 patients on HAART (5%). The incidence of mortality decreased over time in HIV-infected patients (P<0.001; chi(2) test for trend), although it has remained approximately five times higher than that for the age-matched general population. AIDS-related events were the most common cause of death (n=95; 40%), although they significantly decreased over time (P<0.001; chi(2) test for trend), whereas liver diseases (P<0.001; chi(2) test for trend) and non-AIDS-defining infections (P=0.008; chi(2) test for trend) significantly increased over time. Infections in general (33 times higher), liver diseases (11 times higher) and non-Hodgkin lymphoma (5 times higher) were overrepresented as causes of death in the HIV-infected cohort compared with the age-matched general population. Non-AIDS-defining infectious diseases, liver diseases, and non-Hodgkin lymphoma represent specific targets for efforts to further decrease mortality in HIV-infected patients receiving HAART.

When time is more than money: The allocation of time between work and leisure in HIV-infected patients

Time is a limited resource and individuals have to decide how many hours they should allocate to work and to leisure activities. Differences in wage rate or availability of non-labour income (financial support from families and savings) may influence how individuals allocate their time between work and leisure. An increase in wage rate may induce income effects (leisure time demanded increases) and substitution effects (leisure time demanded decreases) whereas an increase in non-labour income only induces income effects. We explored the effects of differences in wage rate and non-labour income on the allocation of time in HIV-infected patients. Patients enrolled in the Swiss HIV Cohort Study (SHCS) provided information on their time allocation, i.e. number of hours worked in 1998. A multinomial logistic regression model was used to test for income and substitution effects. Our results indicate that (i) the allocation of time in HIV-infected patients does not differ with level of education (i.e., wage rate), and that (ii) availability of non-labour income induces income effects, i.e. individuals demand more leisure time.

Modelling the association between adherence and viral load in HIV-infected patients

The primary objective of this paper is to investigate the effect of adherence to prescribed antiretroviral therapy on virologic response measured repeatedly over time in HIV-infected patients. To this end observations on plasma viral load (HIV RNA) assessed in copies/ml are categorized into four clinically meaningful states, [0--50[, [50--400[, [400--2000[, [2000 and up. A time-dependent continuation ratio model is used to analyse longitudinal ordinal responses. The main challenge lies in modelling dependencies over time and using information contained in the data efficiently to establish a dynamic relation between observed patient adherence and viral load. Among the several measures of adherence investigated, two specifically account for long periods of time without intake. One is derived from the third moment of the inter-dose interval distribution, while the second reflects internal drug exposure using pharmacokinetic parameters. The approach is applied to a clinical trial involving 35 patients who were followed over 12 months. Results demonstrate a significant relation between patient adherence and virologic response.

Changes in Viral Load in People with Virological Failure who Remain on the Same Haart Regimen

To assess the rate of change in viral load and CD4 count over time in HIV-infected patients experiencing virological failure on a HAART regimen. Study population included patients from EuroSIDA, a large, multicentre, observational study enrolling HIV-infected patients across Europe. Median change in viral load and CD4 count per month were estimated using the viral load and CD4 measurements obtained over a 12-month period after confirmed virological failure between 3 and 4 log10 copies/ml in a population of 488 HIV-infected patients who were left on a failing HAART regimen. The estimated median viral load change in our study population was 0.024 log10 copies/ml per month, statistically different from 0 (P=0.0001). In 20.9% of the patients studied viral load showed a tendency to decrease, in 47.8% showed a tendency to increase by a positive rate no higher than 0.04 log10 copies/ml per month and in the remaining 31.3% showed a tendency to increase by a rate greater than 0.04 log10 copies/ml per month. On average, CD4 counts were estimated to remain stable (decrease at a slow rate of about -0.53 cells/microl per month). In patients that remained on a stable, but virologically failing HAART regimen (with viral load ranging 1000-10000 copies/ml), the viral load over the ensuing 12-month period increased at a relatively slow rate. In contrast, the CD4 count remained stable, possibly because of partial but sustained viral suppression below the viral load natural set-point. The time-course of selecting more replication-competent virus in patients with virological failure remains to be fully clarified.

Stable or increasing bone mineral density in HIV-infected patients treated with nelfinavir or indinavir.

To determine the factors contributing to changes in bone mineral density (BMD) over time in HIV-infected patients receiving highly active antiretroviral therapy (HAART). Analyses of lumbar spine BMD in 183 male Caucasian participants in the Western Australian HIV Cohort study, comprising a longitudinal analysis of data from 54 patients on stable HAART regimens, and a cross-sectional analysis comparing data from 131 protease inhibitor (PI)-treated patients and 52 PI-naive (including 28 antiretroviral treatment-naive) patients. Average lumbar spine BMD remained stable or increased over the time frame considered. Although there was no evidence of a change of average BMD over time in patients receiving nelfinavir (P = 0.92), there was evidence of increasing bone density in the indinavir group (average increase, 0.31 z-score per year; P < 0.001). Lower initial z-scores in the longitudinal analysis were significantly associated with lower pre-HAART BMI (P = 0.003), consistent with results of the cross-sectional analysis in which lowest BMI prior to initial dual X-ray absorptiometry scan was associated with decreased BMD (P = 0.02, overall group). Although PI therapy was also associated with decreased BMD in a univariate analysis of the cross-sectional data (P = 0.04), this effect was abrogated in a multiple linear regression analysis (P = 0.11) with lowest BMI remaining significant (P = 0.04). We found no evidence, overall, of accelerated bone loss in patients treated with nelfinavir- or indinavir-containing HAART regimens, and propose that indinavir therapy may be associated with an increase in bone mineral density over time. Pre-HAART BMI was an independent and powerful determinant of an individual's initial z-score in the longitudinal analysis, and adjustment for this effect in a cross-sectional analysis abrogated the association between PI therapy and decreased lumbar spine z-score.

Decreased exposure to saquinavir in HIV-1-infected patients after long-term antiretroviral therapy including ritonavir and saquinavir.

To explore whether steady-state plasma pharmacokinetics of ritonavir and saquinavir change during long-term treatment in HIV-1-infected patients on antiretroviral treatment including ritonavir and saquinavir. The pharmacokinetics of ritonavir and saquinavir were assessed during an 8-h period on two occasions in six HIV-1 infected patients on stable twice daily treatment with ritonavir 400 mg, saquinavir 400 mg and stavudine 40 mg with or without lamivudine 150 mg twice daily. The first study day was 4-12 months (median 7 months) after the start of the current regimen. The second study day was 9-15 months (median 10 months) later. No significant differences were observed for the ritonavir pharmacokinetics between the first and second study day. However, median change in plasma trough level of saquinavir between the two study days was -30% (range -79 to +11%; P = 0.06). Median change in maximum plasma concentration was -40% (range -62 to +34%; P = 0.09). The median change in area under the plasma concentration versus time curve over 0-8 h was -33% (range -53 to +21%; P = 0.06). The exposure to saquinavir decreased over time in HIV-infected patients on stable antiretroviral therapy. These data suggest that regular monitoring of plasma drug concentrations should become part of routine patient care even in apparently compliant patients.

Long-term survival in patients with advanced immunodeficiency.

To identity prognostic factors associated with survival time in HIV-infected patients with advanced immunodeficiency. Prospective cohort study. A total of 1284 HIV-infected patients with serial CD4 count measurements and at least one CD4 cell count < or = 50 x 10(6)/I (CD4 < or = 50). Survival from initial CD4 cell count < or = 50 x 10(6)/l. The median survival from initial CD4 < or = 50 x 10(6)/l was 17.1 months. The risk of death increased by 2% 195% confidence interval (Cl), 1-31 for each year of age, by 10% (95% Cl, 3-16) for each 10 x 10(6)/l decrease in CD4 count, and by 14% (95% Cl, 9-18) for each 1 g/dl decrease in haemoglobin level. Compared to AIDS-free patients with CD4 < or = 50 x 10(6) cells/l, the risk of dying was 1.5-fold (95% Cl, 1.2-1.9) that of patients who had an AIDS diagnosis for fewer than 3 months prior to CD4 < or = 50, 1.8-fold for patients with an AIDS diagnosis for 4-11 months prior to CD4 < or = 50, and twice that of patients with AIDS for > or = 12 months prior to CD4 < or = 50. The risk of dying for patients whose rate of CD4 cell decline was > 40 x 10(6)/l per 6 months was 1.7-fold (95% Cl, 1.3-2.3) that of patients with an average CD4 cell loss < 40 x 10(6)/l per 6 months, after adjusting for age, haemoglobin and duration of AIDS prior to CD4 < or = 50 x 10(6) cells/l. A prognostic score was developed from the final multivariate model, based on age at CD4 < or = 50, haemoglobin at CD4 < or = 50, duration of AIDS and rate of CD4 decline prior to CD4 < or = 50. Routinely available clinical and laboratory data including haemoglobin level, rate of CD4 decline and duration of AIDS can be readily translated into a prognostic score and then used to predict the survival experience of an HIV-infected patient with advanced immunodeficiency.