Hartmut B Krentz

Hartmut B Krentz
Alberta Health Services · Southern Alberta Clinic

PhD

About

86
Publications
6,839
Reads
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2,260
Citations
Citations since 2017
31 Research Items
908 Citations
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Introduction
Skills and Expertise

Publications

Publications (86)
Article
Unsuppressed HIV viremia damages immunity and increases the risk for secondary HIV transmission. Successful engagement of persons with HIV (PWH) into care resulting in viral suppression is vital. PWH already engaged in care, who, after achieving viral suppression, experience viral breakthrough episodes (VBEs) with a sequence of suppressed/unsuppres...
Article
Full-text available
Background Varicella-zoster virus (VZV) infection disproportionately affects people with HIV (PWH) primarily presenting as Herpes Zoster. However, VZV seroprevalence, its association with zoster, and clinical outcomes, remain understudied in era of modern antiretroviral therapy (ART). We assessed VZV seroprevalence, rates of VZV illness, and associ...
Article
Background: Many challenges remain in successfully engaging people with HIV (PWH) into lifelong HIV care. Living in non-urban or rural areas has been associated with worse outcomes. Uncertainties remain regarding how to provide optimal HIV care in non-urban areas. Methods: Using a retrospective descriptive analysis framework, we compared multipl...
Article
The emergence of dual therapy for antiretroviral (ARV)-experienced persons living with HIV (PWH) offers the opportunity to reduce lifetime exposure to unnecessary ARV drugs while maintaining viral suppression and reducing the cost of care. Our objective, using retrospective analysis of a quality care initiative, was to examine in routine clinical p...
Article
We aimed to identify “high-cost” patients with HIV (PWH) and determine drivers behind higher costs. All PWH at the Southern Alberta HIV Clinic, Canada, and active in 2017 were included. Sociodemographic, clinical, and healthcare utilization data were collected. The direct care costs from the payers’ perspective including antiretroviral drugs (ARV),...
Article
Background The economic consequences of a missed opportunity for HIV testing at an earlier stage of infection within a healthcare setting are poorly described. Methods For all newly diagnosed HIV patients followed at the Southern Alberta HIV/AIDS Clinic (SAC), Calgary, Canada, between 1 April 2011 and 1 April 2016, all clinical encounters occurrin...
Article
Objective: To examine the impact of previous interpersonal violence (IPersV) experiences on long-term healthcare engagement and health outcomes in a large Canadian HIV-cohort. Design: People living with HIV (PLHIV) were screened for IPersV, and their healthcare outcomes over the nine subsequent years were analyzed. Methods: A total of 1064 PLH...
Article
Despite guidelines, many individuals are not routinely tested for HIV within healthcare settings. Our objective was to quantify and characterize preceding clinical encounters by newly-diagnosed persons living with HIV in southern Alberta, Canada. We discuss the clinical impact of missed HIV testing, and options for remediation. Clinical encounters...
Article
Retention in care remains an important concern for health care providers. However, accurately identifying who is or is not retained in care can be problematic. Not all patients believed to be engaged in care are actually in care, and not all patients believed to be disengaged are truly disengaged. Identifying the status of individuals within popula...
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Background The aim of the present study was to calculate a frailty index (FI) in older adults (≥50) living with HIV, search for cross-sectional associations with the FI, and investigate the association between the FI score and two-year mortality. Methods Cross-sectional study with a short-term prospective com-ponent for the determination of two-yea...
Article
Objectives: The aim of the study was to reappraise the precise costs of HIV care and cost drivers, to determine the optimal tools for modelling costs for HIV care, and to understand the implications of changing medical management of HIV-infected patients for both subsequent outcomes and health care budgets. Methods: We obtained all drug, laborat...
Article
Scientific medical conferences have proliferated in recent years but little data are available to assess their effectiveness in achieving their commonly stated aims “to educate, advance science, and establish evidence-based policy”. The recent expansion of what has been labeled ‘predatory academia’ has heightened concerns about the quality of both...
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Background Baseline genotype antiretroviral resistance testing (GART) were introduced to allow better selection of antiretroviral therapy (ART), minimizing the use of less effective drugs and risk for ongoing transmission of drug-resistant virus. However, the value of baseline GART has recently been questioned due to declining incidence of TDR in t...
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Background Cross-sectional reporting of viral suppression rates within a population underestimates the community viral load (VL) burden. Longitudinal approaches, while addressing cumulative effects, may still underestimate viral burden if ‘churn’ (movement in and out of care) is not incorporated. We examined the impact of churn on the cumulative co...
Article
Objectives As more HIV‐positive individuals receive antiretroviral therapy (ART), payers are seeking options for covering these increased and sustained drug costs. Strategic use of available generic antiretroviral (ARV) formulations may be feasible. De‐simplifying a single‐tablet co‐formulation (STF) into two or more tablets using both brand and ge...
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Introduction:: The use of lifelong antiretroviral therapy (ART) results in increased costs of care; the ability to finance and control sustained costs of ART needs to be discussed. Approach:: The Southern Alberta Clinic initiated a practical cost savings approach that switched select patients from a branded ART to a less expensive generic variat...
Article
With an ever increasing number of academic conferences being offered and a growing concern regarding the appearance of “predatory conferencing”, the optimal use of one’s “conference time” has become complicated. It is particularly important for medical students and residents, due to both limited time and resources, to choose conferences to achieve...
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Background The incidence of AIDS defining CNS infections declined significantly with HAART; however, the longitudinal change in factors and effects of disease has not been well described. We characterized the changing incidence and outcomes in AIDS defining CNS infections over the past 30 years in the geographically defined, well-characterized sout...
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Objectives Syphilis is a global health concern with an estimated 12 million infections occurring annually. Due to the increasing rates of new syphilis infections being reported in patients infected with HIV, and their higher risk for atypical and severe presentations, periodic screening has been recommended as a routine component of HIV care. We ai...
Article
Individuals diagnosed with HIV before 1996 had poor prognoses. Few HIV care centers can track patients continuously from the 1980s to present. We determined the sociodemographic, clinical, and health care utilization characteristics of patients diagnosed and followed for >20 years (i.e. long-term HIV/AIDS survivors) to understand what factors contr...
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Background: Syphilis is a global health concern disproportionately affecting HIV-infected populations. In Alberta, Canada, the incidence of syphilis in the general population has recently doubled with 25% of these infections occurring in HIV-infected patients. The Southern Alberta HIV Clinic (SAC) and Calgary STI Program (CSTI) analyzed the epidem...
Article
Objectives: The incremental costs of expanding antiretroviral (ARV) drug treatment to all HIV-infected patients are substantial, so cost-saving initiatives are important. Our objectives were to determine the acceptability and financial impact of de-simplifying (i.e. switching) more expensive single-tablet formulations (STFs) to less expensive gene...
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Background Syphilis is an emerging global health concern with an estimated 12 million new infections being documented annually. In individuals with HIV, syphilis presentations may be atypical leading to the recommendation for regular routine screening. This retrospective cohort study aimed to characterize syphilis presentation and serologic feature...
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The aim of the proposed study is to estimate the period prevalence of frailty using two different approaches in a cohort of HIV patients engaged in care at the Southern Alberta Clinic. This population differs from previous studies of frailty in HIV by the inclusion of a broad and heterogeneous patient population. Another novel element will be the u...
Article
Background: Clinical guidelines recommend immediate initiation of combined antiretroviral therapy (ART) for all HIV-positive individuals. However, those guidelines are based on trials of relatively young participants. Methods: We included HIV-positive ART-naïve, AIDS-free individuals aged 50-70 years after 2004 in the HIV-CAUSAL Collaboration. W...
Article
In the United States 40% of HIV patients are lost to follow-up (LTFU) following linkage to HIV care and an estimated 30–61% of new HIV transmissions are attributed to this group. To characterize those LTFU and healthcare contacts they make, we retrospectively analyzed a large regional HIV cohort in Calgary, Canada, utilizing a province-wide electro...
Article
Background: Failure to achieve complete viral suppression with antiretroviral drugs (ARV) may lead to uncontrolled HIV replication, ARV resistance, and negative outcomes. Monitoring and reporting of HIV resistance trends is important but problematic. We examined prevalent resistance rates in a HIV population over 20 years and document how rates ma...
Article
Despite strong evidence of a clinical benefit from initiating antiretroviral therapy (ART) immediately after diagnosis some patients remain ART naïve. We examined explanations, over a four-year period in a centralized HIV clinical cohort under universal health care, for newly diagnosed patients, while being fully engaged and retained in HIV care, d...
Article
With improved life expectancy, the medical records of HIV-infected patients are likely to be transferred repeatedly between HIV caregivers. The challenges, and risk for introducing medical error from incomplete record transfers are poorly understood. We measured number of requests for record transfer, the workload incurred, and explore, using genot...
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Improved survival achieved by many patients with HIV/AIDS has complicated their medical care as increasing numbers of co-morbidities leads to polypharmacy, increased pill burdens, and greater risks of drug-drug interactions potentially compromising antiretroviral treatment (ART). We examined the impact of non-antiretroviral polypharmacy on ART for...
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The burden of interpersonal violence (IPV) among those living with HIV is significant. At the Southern Alberta Clinic in Calgary, Alberta, there has been ongoing attention given to the interplay of IPV and HIV. Our data reveal the potential risks, specifically physical harm, emotional suffering, and, in turn, lack of follow-through on HIV medical c...
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Continuity of care is the cornerstone of all modern HIV disease management guidelines. Interruptions in care due to disengagement or moving between HIV care centers are common occurrences often contributing to poorer health. In order to understand why patients disengage from HIV care we first document movement into and out of our regional populatio...
Article
HIV and intimate partner violence (IPV) epidemics propagate and interact in a syndemic fashion contributing to excess burden of disease and poorer health outcomes. In order to understand the impact of IPV on HIV disease management, a universal screening program was implemented in the Southern Alberta Clinic in May 2009. We evaluated our IPV screeni...
Article
Background: The Cascade of Care (COC) visualizes stages of HIV care progression within a population. It is predicated on a local population model and thus may not address the impact on the COC of HIV-experienced individuals diagnosed and cared for elsewhere who move into the area. Methods: All individuals with a confirmed HIV+ test in Calgary, C...
Article
Objectives Improved survival has shifted the HIV epidemic in the developed world towards more individuals > 50 years of age. Older individuals, with new or longstanding HIV infection, are at greater risk for HIV-related and non-HIV-related conditions, compounding the burden and complexity of HIV management. The aim of the study was to examine the i...
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The "cascade of care" displays the proportion of individuals who are infected with human immunodeficiency virus (HIV), diagnosed, linked, retained, on antiretroviral treatment, and HIV suppressed. We examined the implications of including death in the use of this cascade for program and public health performance metrics. Individuals newly diagnosed...
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Antiretroviral drug resistance (ARV) limits choices often necessitating the selection of drugs with less desirable pill burdens, toxicity profiles, drug interactions, dosing schedules, and may increase cost. We examine the impact of resistance on the cost of HIV care. All adult HIV-positive individuals newly referred for HIV care from 1/1/2007-1/1/...
Article
The concept of community viral load (CVL) was introduced to quantify the pool of transmissible HIV within a community and to monitor the potential impact of highly active antiretroviral therapy (HAART) on reducing new infections. The implications of churn (patient movement in/out of care in a community) on CVL have not been studied. The annual CVL...
Article
Full-text available
Intimate partner violence (IPV) is a common and negative social determinant of health. IPV also increases vulnerability to risks associated with HIV transmission and contributes to HIV transmission. IPV is therefore predictably common among people living with HIV. It is increasingly being recognized as an important predictor of poor outcomes for th...
Article
Introduction: Intimate partner violence (IPV) is associated with increased risk of HIV infection among women, however, whether IPV affects outcomes after HIV infection is uncertain. We assess the impact of IPV on HIV-positive women. Methods: All HIV-positive women who received outpatient HIV care in southern Alberta between March 2009 and Januar...
Article
Background: Retention in care is key to improving HIV outcomes. The goal of this study was to describe 'churn' in patterns of entry, exit, and retention in HIV care in the United States and Canada. Methods: Adults contributing ≥1 CD4 count or HIV-1 RNA (HIV-lab) from 2000 to 2008 in North American AIDS Cohort Collaboration on Research and Design...
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Intimate partner violence (IPV) is a risk factor for HIV infection. Little is known, however, about the prevalence, clinical associations, and impact of IPV among patients living with HIV. HIV-infected gay and bisexual men in Southern Alberta, Canada were screened for IPV between May 2009 and December 2011. The associations with IPV of sociodemogra...
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New antiretroviral (ARV) drugs and improved formulations and coformulations of existing ARVs are actively promoted to diminish a patient's pill burden and to minimise the opportunity for mismatched dosing, although the effect of these advances is poorly understood. We determine how these changes affect the total daily pill burden (TDPB) for ARV and...
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We describe the immediate- and longer-term direct medical costs of care for individuals diagnosed with HIV at CD4 counts <350/mm(3) ("late presenters"). We collected and stratified by initial CD4 count all inpatient, outpatient, and drug costs for all newly diagnosed patients accessing HIV care within Southern Alberta from 1/1/1995 to 1/1/2010. 59%...
Article
To compare the direct cost of care for Canadian and non-Canadian born HIV patients accessing initial HIV care. Drug, inpatient, and outpatient costs were collected for patients initiating HIV care at the Southern Alberta Clinic between 1/1/2000 and 3/31/2008 and followed until 3/31/2009. Demographic/clinical characteristics were obtained at initial...
Article
Studies on patient mobility have focused on patients who become lost-to-follow-up (LTFU). Much less is known about patients who move with a planned transfer of care from one HIV center to another. We assess disease progression in patients who moved and then returned to our care compared with patients remaining or were LTFU. We identified which pati...
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There is a strong association between domestic violence victimization and HIV infection. This may lead to poor health outcomes including mental health disorders and reduced access to care. A standardized domestic violence screening interview was incorporated into ongoing care in the large and diverse population living with HIV in Southern Alberta,...
Article
We determined that for HIV patients presenting with CD4 cell counts less than 350 μl the initial higher costs of care persisted over 5 years. Fifty-nine percent of new patients between 1 April 1998 and 1 April 2003 had CD4 cell counts less than 350 μl. Mean first year total costs ($19 917 $Cdn) were 2.5 times higher than for presentations with CD4...
Article
Combination antiretroviral therapy (cART) has improved the survival of patients with HIV/AIDS but its impact remains uncertain on the changing prevalence and incidence of neurologic disorders with ensuing effects on mortality. The prevalence and incidence of neurologic disorders were examined in patients receiving active care in a regional HIV care...
Data
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Figure S1. Liver toxicity of AEDs. (A) and (B) Based on ACTG guidelines, aviremic patients with concurrent AED use had similar aspartate aminotransferase (AST) and alkaline phosphatise abnormalities to viremic patients (3A and 3B). In contrast, aviremic patients showed a trend toward lower hyperbilirubinemia (3E). Both aviremic and viremic patients...
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Anti-epileptic drugs (AEDs) are frequently prescribed to persons with HIV/AIDS receiving combination antiretroviral therapy (cART) although the extent of AED use and their interactions with cART are uncertain. Herein, AED usage, associated toxicities and immune consequences were investigated. HIV replication was analysed in proliferating human T ce...
Article
High levels of geographic mobility in and out of HIV care centres (i.e. the churn effect) can disrupt the continuity of patient care, misalign prevention services, impact local prevalence data perturbing optimal allocation of resources, and contribute to logical challenges in repeated transfer of health records. We report on the clinical, demograph...
Article
To evaluate the impact of policy changes to Canada's Immigration Act and changing migration patterns on a regional HIV population. All HIV-positive individuals enrolled in care at the Southern Alberta Cohort between 2001 and 2007 were included and subdivided by self-reported country of birth. Demographic, clinical, and health utilization data were...
Article
To report on the cost of medical care for HIV-infected patients stratified by CD4 cell count for a regional population over a 9-year period, and to examine the effect of reporting costs of HIV care only or only in antiretroviral therapy (ART)-experienced patients. Retrospective costing analysis on all HIV-infected patients within the Southern Alber...
Article
We used the 13% of patients in our regional population with HIV diagnosis by existing healthy population–based screening (insurance, blood donation, immigration, and pregnancy) as a guide for measuring the anticipated acuity of new patients and then stratified their costs by CD4⁺ cell count by using our costing data (4). Of all healthy HIV-infected...
Article
HAART is associated with a growing prevalence of HIV-associated neuropsychiatric disorders (NPD) despite improved overall survival. To investigate the added direct costs of medical care for patients with and without NPD. Nine dimensions of patient-specific costs [as costs per patient per month (CPM)] were followed prospectively between 1997 and 200...
Article
To determine the frequency of and reasons for hospitalization of adult HIV-infected patients compared with the general population. Length of stay, primary/secondary diagnoses and discharge status were reviewed for all HIV-infected patients admitted to Calgary-area hospitals between 1995 and 2003. Admissions were classified as HIV- or non-HIV-relate...
Article
Human immunodeficiency virus-associated sensory neuropathy (HIV-SN) is a common and disabling disorder, often associated with antiretroviral therapy (ART) use. We investigated the clinical features and associated pathogenic determinants of HIV-SN in a neurological cohort of HIV-infected patients, together with a novel model of HIV-SN. HIV-infected...
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Triple-combination antiretroviral therapy (CART) for human immunodeficiency virus infection has been in use for almost a decade, but the extent to which treatment success has changed is uncertain. We examined risk of initial virological failure of CART according to the year of starting therapy. We included subjects from 5 complete clinic cohorts in...
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Background: Triple-combination antiretroviral therapy (CART) for human immunodeficiency virus infection has been in use for almost a decade, but the extent to which treatment success has changed is uncertain. We examined risk of initial virological failure of CART according to the year of starting therapy. Methods: We included subjects from 5 comp...
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This study examined the relationships of income, employment status and other socioeconomic characteristics with dimensions of health-related quality of life (HRQOL) for those living with HIV/AIDS, controlling for clinical characteristics. Demographic (gender, age, education, living with a partner, HIV transmission category), economic (employment st...
Article
Background Antiretroviral (ARV) drugs account for >70% of the direct costs of HIV care. Changing practices in the use of ARV drugs may have major cost implications for the care budget within a regional population. Objective To characterize and quantify the precise changes in the use of ARV within an entire HIV-infected population and to develop an...
Article
Full-text available
Human immunodeficiency virus (HIV) infection frequently results in neurological complications but the impact of different neurological syndromes on patients' quality of life remains unknown. We investigated health-related quality of life (HRQoL) parameters among HIV/Acquired Immune Deficiency Syndrome (AIDS) patients with and without neurological d...
Article
To examine changes over a 2-year period in both the mortality rate and the causes of death in a geographically defined HIV-infected population. A database search of primary care information for the dates and causes of death for all patients documented with HIV infection and living in Southern Alberta between 1984 and 2003 was undertaken. Sociodemog...
Article
To compare the direct costs of medical care in the year following HIV diagnosis for patients who present with a CD4 count <200 cells/microL ('late presenters') and those who present with a CD4 count >200 cells/microL ('early presenters'). Direct costs (i.e. drugs, laboratory tests, outpatient care, in-patient care, and home care) for the 12 months...
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Full-text available
Determining the direct cost of providing medical care to patients with HIV/AIDS is important for both short-term and long-term decision-making and for appropriate resource allocation. We aimed to categorize and measure the direct costs of medical care provided to the entire HIV-positive population receiving care in southern Alberta between 1995 and...
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To examine health-related quality of life (HRQOL) before, during and after treatment interruptions (TI) in antiretroviral therapy, we analysed results from Medical Outcomes Study HIV health surveys on 50 HIV-1-infected patients. HRQOL scores decreased during a TI but increased after re-initiating treatment, although scores remained lower than those...
Article
Concentrations of small fossil mammals are frequently encountered in Cenozoic deposits, but the causes for such accumulations have seldom been determined. In many cases the tooth, jaw, and limb fragments appear to be well-preserved under light microscopy, and it is difficult to differentiate damage due to predator digestion from breakage and abrasi...
Article
Thesis (Ph. D.)--University of Washington, 1993 Isolated forelimb postcrania from the Shungura Formation, Ethiopia are assigned to Theropithecus brumpti or Theropithecus oswaldi based on anatomical comparisons with extant and extinct species of cercopithecoids. The analysis of characters on the humeri, ulnae, and radii show that theropithecine fore...

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