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1.
Am J Trop Med Hyg ; 109(2): 466-470, 2023 08 02.
Article in English | MEDLINE | ID: mdl-37364863

ABSTRACT

It remains unclear whether a previous history of tropical infectious diseases and a second SARS-COV-2 infection may influence the likelihood of later symptoms. In this prospective cohort study, individuals infected with SARS-CoV-2 were followed up by telephone shortly after diagnosis of COVID-19 and again 12 months later. Poisson regression was used to identify the predictors of the highest number of symptoms in the post-COVID-19 syndrome. A total of 1,371 patients with COVID-19, with a mean age of 39.7 ± 11.7 years and 50% female, were followed for 12 months. Reinfection was found in 32 (2.3%) participants, and 806 (58.8%) individuals reported a previous history of dengue, malaria, Zika, chikungunya, leprosy, and visceral leishmaniasis. Eight hundred seventy-seven (63.9%) participants reported late symptoms related to COVID-19. After adjusting for multiple factors, female sex, non-White race, number of acute-phase symptoms, body mass index, and reinfection were independent predictors of higher number of symptoms in post-COVID-19 syndrome. Female sex, non-White race, number of acute-phase symptoms, body mass index, and reinfection, but not previous endemic tropical diseases, were associated with long-term symptoms.


Subject(s)
COVID-19 , Zika Virus Infection , Zika Virus , Humans , Female , Adult , Middle Aged , Male , COVID-19/epidemiology , Cohort Studies , Prevalence , SARS-CoV-2 , Post-Acute COVID-19 Syndrome , Prospective Studies , Reinfection
2.
J Infect Dis ; 225(9): 1601-1610, 2022 05 04.
Article in English | MEDLINE | ID: mdl-34623435

ABSTRACT

BACKGROUND: Chagas disease affects an estimated 326 000-347 000 people in the United States and is severely underdiagnosed. Lack of awareness and clarity regarding screening and diagnosis is a key barrier. This article provides straightforward recommendations, with the goal of simplifying identification and testing of people at risk for US healthcare providers. METHODS: A multidisciplinary working group of clinicians and researchers with expertise in Chagas disease agreed on 6 main questions, and developed recommendations based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology, after reviewing the relevant literature on Chagas disease in the United States. RESULTS: Individuals who were born or resided for prolonged time periods in endemic countries of Mexico and Central and South America should be tested for Trypanosoma cruzi infection, and family members of people who test positive should be screened. Women of childbearing age with risk factors and infants born to seropositive mothers deserve special consideration due to the risk of vertical transmission. Diagnostic testing for chronic T. cruzi infection should be conducted using 2 distinct assays. CONCLUSIONS: Increasing provider-directed screening for T. cruzi infection is key to addressing this neglected public health challenge in the United States.


Subject(s)
Chagas Disease , Trypanosoma cruzi , Chagas Disease/diagnosis , Chagas Disease/epidemiology , Female , Humans , Infant , Infectious Disease Transmission, Vertical/prevention & control , Mass Screening , Mothers , United States/epidemiology
3.
Emerg Infect Dis ; 27(9): 2462-2465, 2021.
Article in English | MEDLINE | ID: mdl-34424171

ABSTRACT

Disseminated cutaneous leishmaniasis (DCL) is an uncommon form of Leishmania braziliensis infection. It remains unknown why some people develop this clinical condition. We describe 14 DCL patients in Northeast Brazil during 2015-2018. These patients regularly drank large amounts of alcohol, possibly increasing their risk for DCL.


Subject(s)
Alcoholism , Leishmania braziliensis , Leishmaniasis, Cutaneous , Brazil/epidemiology , Ethanol , Humans , Leishmaniasis, Cutaneous/diagnosis , Leishmaniasis, Cutaneous/epidemiology
4.
JBJS Case Connect ; 11(2)2021 06 23.
Article in English | MEDLINE | ID: mdl-34161307

ABSTRACT

CASE: We describe the case of a 74-year-old man who developed severe hip pain several days after an intra-articular methylprednisolone injection to his right hip. Culture of the ipsilateral iliopsoas bursa revealed a Staphylococcus lugdunensis infection, which was successfully eradicated through irrigation and debridement as well as antibiotics. CONCLUSION: Infection after hip injection is a known theoretical risk but is rarely reported in the literature. We present a case of septic bursitis after corticosteroid injection. Readers should be mindful that these complications do occur in clinical practice and portend significant morbidity.


Subject(s)
Bursitis , Methylprednisolone , Aged , Bursitis/complications , Bursitis/drug therapy , Hip , Hip Joint , Humans , Injections, Intra-Articular/adverse effects , Male , Methylprednisolone/adverse effects
5.
Clin Infect Dis ; 72(6): 1084-1092, 2021 03 15.
Article in English | MEDLINE | ID: mdl-32772104

ABSTRACT

Orally-transmitted acute Chagas disease (CD) is emerging as an important public health problem. The prognosis of acute infection following oral transmission is unknown. The aim of this study was to analyze and summarize data on orally-transmitted acute CD. We searched for publications from 1968 to 31 January 2018. We included studies and unpublished data from government sources that reported patients with acute orally-transmitted CD. We identified 41 papers and we added 932 unpublished cases. In all, our study covered 2470 cases and occurrence of 97 deaths. Our meta-analysis estimated that the case-fatality rate was 1.0% (95% CI 0.0-4.0%). Lethality rates have declined over time (P = .02). In conclusion, orally-transmitted acute CD has considerable lethality in the first year after infection. The lethality in symptomatic cases is similar to that from other routes of infection. The lethality rate of orally-acquired disease has declined over the years.


Subject(s)
Chagas Disease , Chagas Disease/epidemiology , Humans , Prognosis
6.
Clin Infect Dis ; 73(5): e1219-e1221, 2021 09 07.
Article in English | MEDLINE | ID: mdl-33373433

ABSTRACT

We studied 2351 participants with coronavirus disease 2019; 1177 (50%) reported previous dengue infection. Those without previous dengue had a higher risk of death (hazard ratio: .44; 95% confidence interval: .22-.89; P = .023) in 60-day follow-up. These findings raise the possibility that dengue might induce immunological protection against severe acute respiratory syndrome coronavirus 2.


Subject(s)
COVID-19 , Dengue , Dengue/epidemiology , Humans , SARS-CoV-2
7.
J Arthroplasty ; 36(3): 1101-1108, 2021 03.
Article in English | MEDLINE | ID: mdl-33160807

ABSTRACT

BACKGROUND: Prosthetic joint infection (PJI) is a morbid complication following total joint arthroplasty (TJA). PJI diagnosis and treatment has changed over time, and patient co-management with a high-volume musculoskeletal infectious disease (MSK ID) specialist has been implemented at our institution in the last decade. METHODS: We retrospectively evaluated all consecutive TJA patients treated for PJI between 1995 and 2018 by a single high-volume revision TJA surgeon. Microbial identities, antibiotic resistance, prior PJI, and MSK ID consultation were investigated. RESULTS: In total, 261 PJI patients (median age 66 years, interquartile range 57-75) were treated. One-year and 5-year reinfection rates were 15.8% (95% confidence interval [CI] 11.6-20.7) and 22.1% (95% CI 17.0-27.7), respectively. Microbial identities and antibiotic resistances did not change significantly over time. Despite seeing more prior PJI patients (53.3% vs 37.6%, P = .012), MSK ID-managed patients had similar infection rates as non-MSK ID-managed patients (hazard ratio [HR] 1.02, 95% CI 0.6-1.75, P = .93). Prior PJI was associated with higher reinfection risk (HR 2.39, 95% CI 1.39-4.12, P = .002) overall and in patients without MSK ID consultation, specifically (HR 2.78, 95% CI 1.37-5.65, P = .005). This risk was somewhat lower and did not reach significance in prior PJI patients with MSK ID consultation (HR 1.97, 95% CI 0.87-4.48, P = .106). CONCLUSION: We noted minimal differences in microbial/antibiotic resistances for PJI over 20 years in a single institution, suggesting current standards of PJI treatment remain encouragingly valid in most cases. MSK ID involvement was not associated with lower reinfection risk overall; however, in patients with prior PJI, the risk of reinfection appeared to be somewhat lower with MSK ID involvement. LEVEL OF EVIDENCE: Level IV-Case Series.


Subject(s)
Arthritis, Infectious , Arthroplasty, Replacement, Hip , Prosthesis-Related Infections , Surgeons , Aged , Arthroplasty, Replacement, Hip/adverse effects , Humans , Prosthesis-Related Infections/epidemiology , Prosthesis-Related Infections/etiology , Prosthesis-Related Infections/surgery , Reoperation , Retrospective Studies , Risk Factors
8.
J Arthroplasty ; 35(11): 3261-3268, 2020 11.
Article in English | MEDLINE | ID: mdl-32709562

ABSTRACT

BACKGROUND: Knee arthrodesis (KA) and above-knee amputation (AKA) have been used for salvage of failed total knee arthroplasty (TKA) after periprosthetic joint infection (PJI). However, few studies have assessed the outcomes of KA after TKA PJI, as it remains an uncommon procedure. We investigated rates of AKA, control of infection, and ambulatory status after KA for TKA PJI treatment. METHODS: This was a retrospective and single-surgeon series of 51 failed TKAs due to PJI treated with two-stage KA between 2000 and 2016 with a minimum of 2-year follow-up. Patient demographics, comorbidities, surgical history, radiographic data, and outcomes of KA treatment were recorded. RESULTS: Infection was successfully controlled in 48 of 51 patients (94.1%); of these, 24 knees (50.0%) required no reoperation subsequent to the index KA, whereas the remaining 24 (50.0%) patients required a median of 1 additional operation. Nonunion, malunion, or delayed union was noted in 10 patients (19.6%). Of the 48 patients who were successfully treated with KA, 41 patients (85.4%) remained ambulatory after KA and 9 of these patients (18.8%) did not require assistive devices. Three of 51 patients (5.9%) progressed to AKA after KA. CONCLUSION: Patients undergoing KA for TKA PJI had high rates of infection control and preservation of ambulatory status, with low rates of progression to AKA in our study. LEVEL OF EVIDENCE: Level IV-case series.


Subject(s)
Arthroplasty, Replacement, Knee , Knee Prosthesis , Prosthesis-Related Infections , Arthrodesis , Arthroplasty, Replacement, Knee/adverse effects , Humans , Knee Prosthesis/adverse effects , Prosthesis-Related Infections/epidemiology , Prosthesis-Related Infections/surgery , Reoperation , Retrospective Studies
9.
PLoS Negl Trop Dis ; 14(6): e0008398, 2020 06.
Article in English | MEDLINE | ID: mdl-32569280

ABSTRACT

Approximately 300,000 persons in the United States (US) are infected with Trypanosoma cruzi, the protozoan that causes Chagas disease, but less than 1% are estimated to have received antiparasitic treatment. Benznidazole was approved by the US Food and Drug Administration (FDA) for treatment of T. cruzi infection in 2017 and commercialized in May 2018. This paper analyzes factors that affect access to benznidazole following commercialization and suggests directions for future actions to expand access. We applied an access framework to identify barriers, facilitators, and key actors that influence the ability of people with Chagas disease to receive appropriate treatment with benznidazole. Data were collected from the published literature, key informants, and commercial databases. We found that the mean number of persons who obtained benznidazole increased from just under 5 when distributed by the CDC to 13 per month after the commercial launch (from May 2018 to February 2019). Nine key barriers to access were identified: lack of multi-sector coordination, failure of health care providers to use a specific order form, lack of an emergency delivery system, high medical costs for uninsured patients, narrow indications for use of benznidazole, lack of treatment guidelines, limited number of qualified treaters, difficulties for patients to make medical appointments, and inadequate evaluation by providers to determine eligibility for treatment. Our analysis shows that access to benznidazole is still limited after FDA approval. We suggest six areas for strategic action for the pharmaceutical company that markets benznidazole and its allied private foundation to expand access to benznidazole in the US. In addition, we recommend expanding the existing researcher-clinician network by including government agencies, companies and others. This paper's approach could be applied to access programs for benznidazole in other countries or for other health products that target neglected populations throughout the world.


Subject(s)
Chagas Disease/drug therapy , Nitroimidazoles/supply & distribution , Nitroimidazoles/therapeutic use , Trypanocidal Agents/supply & distribution , Trypanocidal Agents/therapeutic use , Age Factors , Centers for Disease Control and Prevention, U.S. , Drug Costs , Drugs, Investigational , Humans , Nitroimidazoles/economics , Trypanocidal Agents/economics , Trypanosoma cruzi , United States , United States Food and Drug Administration
10.
Arthroplast Today ; 5(4): 427-430, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31886384

ABSTRACT

A 61-year-old woman with a right total knee arthroplasty presented with 1 week of atraumatic right knee swelling, pain, and fevers 2 weeks following a routine screening colonoscopy. Aspiration was concerning for prosthetic joint infection and she underwent definitive treatment with irrigation and debridement with polyethylene exchange followed by a 6-week course of oral metronidazole. Cultures speciated as Bacteroides fragilis with the presumed source being the colonoscopy causing transient bacteremia and subsequent seeding of the right knee. This case highlights the need for consideration of guidelines regarding prophylactic antibiotics to prevent prosthetic joint infection after endoscopic procedures.

11.
Clin Microbiol Rev ; 33(1)2019 12 18.
Article in English | MEDLINE | ID: mdl-31776135

ABSTRACT

Trypanosoma cruzi is the etiological agent of Chagas disease, usually transmitted by triatomine vectors. An estimated 20 to 30% of infected individuals develop potentially lethal cardiac or gastrointestinal disease. Sylvatic transmission cycles exist in the southern United States, involving 11 triatomine vector species and infected mammals such as rodents, opossums, and dogs. Nevertheless, imported chronic T. cruzi infections in migrants from Latin America vastly outnumber locally acquired human cases. Benznidazole is now FDA approved, and clinical and public health efforts are under way by researchers and health departments in a number of states. Making progress will require efforts to improve awareness among providers and patients, data on diagnostic test performance and expanded availability of confirmatory testing, and evidence-based strategies to improve access to appropriate management of Chagas disease in the United States.


Subject(s)
Chagas Disease/epidemiology , Chagas Disease/parasitology , Trypanosoma cruzi , Chagas Disease/diagnosis , Chagas Disease/transmission , Disease Management , Disease Susceptibility , Humans , Molecular Diagnostic Techniques , Molecular Epidemiology , Phenotype , Public Health Surveillance , Trypanosoma cruzi/classification , Trypanosoma cruzi/genetics , United States/epidemiology
13.
N Engl J Med ; 376(10): 939-946, 2017 03 09.
Article in English | MEDLINE | ID: mdl-28273010

ABSTRACT

Background Babesiosis, a tickborne zoonotic disease caused by intraerythrocytic protozoa of the genus babesia, is characterized by nonimmune hemolytic anemia that resolves with antimicrobial treatment and clearance of parasitemia. The development of warm-antibody autoimmune hemolytic anemia (also known as warm autoimmune hemolytic anemia [WAHA]) in patients with babesiosis has not previously been well described. Methods After the observation of sporadic cases of WAHA that occurred after treatment of patients for babesiosis, we conducted a retrospective cohort study of all the patients with babesiosis who were cared for at our center from January 2009 through June 2016. Data on covariates of interest were extracted from the medical records, including any hematologic complications that occurred within 3 months after the diagnosis and treatment of babesiosis. Results A total of 86 patients received a diagnosis of babesiosis during the 7.5-year study period; 18 of these patients were asplenic. WAHA developed in 6 patients 2 to 4 weeks after the diagnosis of babesiosis, by which time all the patients had had clinical and laboratory responses to antimicrobial treatment of babesiosis, including clearance of Babesia microti parasitemia. All 6 patients were asplenic (P<0.001) and had positive direct antiglobulin tests for IgG and complement component 3; warm autoantibodies were identified in all these patients. No alternative explanation for clinical hemolysis was found. WAHA required immunosuppressive treatment in 4 of the 6 patients. Conclusions We documented post-babesiosis WAHA in patients who did not have a history of autoimmunity; asplenic patients appeared to be particularly at risk.


Subject(s)
Anemia, Hemolytic, Autoimmune/parasitology , Babesia microti , Babesiosis/complications , Splenectomy/adverse effects , Adult , Anemia, Hemolytic, Autoimmune/immunology , Autoantibodies/blood , Babesia microti/immunology , Babesia microti/isolation & purification , Babesiosis/drug therapy , Female , Humans , Male , Risk Factors , Transfusion Reaction
14.
Aesthet Surg J ; 36(8): NP246-53, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27095310

ABSTRACT

BACKGROUND: "Medical tourism" has gained popularity over the past few decades. This is particularly common with patients seeking elective cosmetic surgery in the developing world. However, the risk of severe and unusual infectious complications appears to be higher than for patients undergoing similar procedures in the United States. OBJECTIVES: The authors describe their experience with atypical mycobacterial infections in cosmetic surgical patients returning to the United States postoperatively. METHODS: A review of patient medical records presenting with infectious complications after cosmetic surgery between January 2010 and July 2015 was performed. Patients presenting with mycobacterial infections following cosmetic surgery were reviewed in detail. An extensive literature review was performed for rapid-growing mycobacteria (RGM) related to cosmetic procedures. RESULTS: Between January 2010 and July 2015, three patients presented to our institution with culture-proven Mycobacterium abscessus at the sites of recent cosmetic surgery. All had surgery performed in the developing world. The mean age of these patients was 36 years (range, 29-44 years). There was a delay of up to 16 weeks between the initial presentation and correct diagnosis. All patients were treated with surgical drainage and combination antibiotics with complete resolution. CONCLUSIONS: We present series of patients with mycobacterial infections after cosmetic surgery in the developing world. This may be related to the endemic nature of these bacteria and/or inadequate sterilization or sterile technique. Due to low domestic incidence of these infections, diagnosis may be difficult and/or delayed. Consulting physicians should have a low threshold to consider atypical etiologies in such scenarios. LEVEL OF EVIDENCE: 5 Therapeutic.


Subject(s)
Medical Tourism , Mycobacterium Infections, Nontuberculous/diagnosis , Mycobacterium Infections, Nontuberculous/therapy , Postoperative Complications/diagnosis , Postoperative Complications/therapy , Surgery, Plastic/adverse effects , Adult , Anti-Bacterial Agents/therapeutic use , Developing Countries , Drainage , Elective Surgical Procedures/adverse effects , Female , Humans
16.
PLoS Negl Trop Dis ; 9(8): e0003974, 2015.
Article in English | MEDLINE | ID: mdl-26252767

ABSTRACT

BACKGROUND: Central American countries face a major challenge in the control of Triatoma dimidiata, a widespread vector of Chagas disease that cannot be eliminated. The key to maintaining the risk of transmission of Trypanosoma cruzi at lowest levels is to sustain surveillance throughout endemic areas. Guatemala, El Salvador, and Honduras integrated community-based vector surveillance into local health systems. Community participation was effective in detection of the vector, but some health services had difficulty sustaining their response to reports of vectors from the population. To date, no research has investigated how best to maintain and reinforce health service responsiveness, especially in resource-limited settings. METHODOLOGY/PRINCIPAL FINDINGS: We reviewed surveillance and response records of 12 health centers in Guatemala, El Salvador, and Honduras from 2008 to 2012 and analyzed the data in relation to the volume of reports of vector infestation, local geography, demography, human resources, managerial approach, and results of interviews with health workers. Health service responsiveness was defined as the percentage of households that reported vector infestation for which the local health service provided indoor residual spraying of insecticide or educational advice. Eight potential determinants of responsiveness were evaluated by linear and mixed-effects multi-linear regression. Health service responsiveness (overall 77.4%) was significantly associated with quarterly monitoring by departmental health offices. Other potential determinants of responsiveness were not found to be significant, partly because of short- and long-term strategies, such as temporary adjustments in manpower and redistribution of tasks among local participants in the effort. CONCLUSIONS/SIGNIFICANCE: Consistent monitoring within the local health system contributes to sustainability of health service responsiveness in community-based vector surveillance of Chagas disease. Even with limited resources, countries can improve health service responsiveness with thoughtful strategies and management practices in the local health systems.


Subject(s)
Chagas Disease/transmission , Insect Control , Insect Vectors/parasitology , Triatoma/parasitology , Trypanosoma cruzi/physiology , Animal Distribution , Animals , Chagas Disease/epidemiology , Chagas Disease/prevention & control , El Salvador/epidemiology , Guatemala/epidemiology , Honduras/epidemiology , Insect Vectors/physiology , Triatoma/physiology
18.
PLoS Negl Trop Dis ; 8(10): e3172, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25357122

ABSTRACT

BACKGROUND: To evaluate the effect of insecticide spraying for vector control and elimination of infected dogs on the incidence of human infection with L. infantum, a randomized community intervention trial was carried out in the city of Teresina, Brazil. METHODS/PRINCIPAL FINDINGS: Within each of ten localities in the city, four blocks were selected and randomized to 4 interventions: 1) spraying houses and animal pens with insecticide; 2) eliminating infected dogs; 3) combination of spraying and eliminating dogs, and 4) nothing. The main outcome is the incidence of infection assessed by the conversion of the Montenegro skin test (MST) after 18 months of follow-up in residents aged ≥ 1 year with no previous history of visceral leishmaniasis (VL). Reactions were measured at 48-72 h, induration of ≥ 5 mm considered positive. Interventions were executed after the baseline interview and repeated 6 and 12 months later. The effects of each type of intervention scheme on the incidence of infection were assessed by calculating relative risks and 95% confidence intervals using Poisson population-averaged regression models with robust variance. Among the 1105 participants, 408 (37%) were MST positive at baseline. Of the 697 negatives, only 423 (61%) were reexamined at the end of the follow-up; 151 (36%) of them converted to a positive MST. Only dog culling had some statistically significant effect on reducing the incidence of infection, with estimates of effectiveness varying between 27% and 52%, depending on the type of analysis performed. CONCLUSIONS/SIGNIFICANCE: In light of the continuous spread of VL in Brazil despite the large scale deployment of insecticide spraying and dog culling, the relatively low to moderate effectiveness of dog culling and the non-significant effect of insecticide spraying on the incidence of human infection, we conclude that there is an urgent need for revision of the Brazilian VL control program.


Subject(s)
Disease Vectors , Dog Diseases/prevention & control , Insecticides/pharmacology , Leishmania infantum , Leishmaniasis, Visceral/prevention & control , Adult , Animals , Brazil/epidemiology , Dogs , Female , Humans , Incidence , Leishmaniasis, Visceral/epidemiology , Leishmaniasis, Visceral/transmission , Leishmaniasis, Visceral/veterinary , Male , Middle Aged
19.
Am J Trop Med Hyg ; 89(2): 345-53, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23817330

ABSTRACT

We conducted active surveillance for kala-azar and post-kala-azar dermal leishmaniasis (PKDL) in a population of 24,814 individuals. Between 2002 and 2010, 1,002 kala-azar and 185 PKDL cases occurred. Median PKDL patient age was 12 years; 9% had no antecedent kala-azar. Cases per 10,000 person-years peaked at 90 for kala-azar (2005) and 28 for PKDL (2007). Cumulative PKDL incidence among kala-azar patients was 17% by 5 years. Kala-azar patients younger than 15 years were more likely than older patients to develop PKDL; no other risk factors were identified. The most common lesions were hypopigmented macules. Of 98 untreated PKDL patients, 48 (49%) patients had resolution, with median time of 19 months. Kala-azar patients showed elevated interferon-γ (IFNγ), tumor necrosis factor-α (TNFα), and interleukin 10 (IL-10). Matrix metalloproteinase 9 (MMP9) and MMP9/tissue inhibitor of matrix metalloproteinase-1 (TIMP1) ratio were significantly higher in PKDL patients than in other groups. PKDL is frequent in Bangladesh and poses a challenge to the current visceral leishmaniasis elimination initiative in the Indian subcontinent.


Subject(s)
Leishmaniasis, Cutaneous/immunology , Leishmaniasis, Cutaneous/pathology , Leishmaniasis, Visceral/complications , Adolescent , Adult , Aged , Antiprotozoal Agents/therapeutic use , Bangladesh/epidemiology , Child , Child, Preschool , Collagenases/blood , Cytokines/blood , Female , Humans , Incidence , Leishmaniasis, Cutaneous/drug therapy , Leishmaniasis, Cutaneous/epidemiology , Leishmaniasis, Visceral/drug therapy , Leishmaniasis, Visceral/epidemiology , Male , Matrix Metalloproteinase Inhibitors/blood , Middle Aged , Risk Factors , Young Adult
20.
Int J Infect Dis ; 16(7): e527-31, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22543295

ABSTRACT

BACKGROUND: In epidemiologic research, incidence is often estimated from data arising from an imperfect diagnostic test performed at unequally spaced intervals over time. METHODS: We developed a likelihood-based method to estimate incidence when disease status is measured imperfectly and assays are performed at multiple unequally spaced visits. We assumed conditional independence, no remission, known constant levels of sensitivity and specificity, and constant incidence rates over time. The method performance was evaluated by examining its bias, accuracy (i.e., mean squared error (MSE)), and coverage probability in a simulation study of 4000 datasets, and then we applied the proposed method to a study of hepatitis C virus (HCV) infection in a cohort of pregnant women in the period 1997-2006. RESULTS: The simulation revealed that our method has minimal bias and low MSE, as well as good coverage probability of the resulting confidence intervals. In the application to HCV study, the standard incidence rate estimate which ignores the imperfections of the diagnostic test (number of events/person-years), was 13.7 new HCV cases per 1000 person-years (95% confidence interval 10.1, 17.4). The adjusted incidence estimates (obtained using our proposed method) ranged from 0.4 cases per 1000 person-years (when sensitivity and specificity were assumed to both be 95%) to 13.7 cases per 1000 person-years (when sensitivity and specificity were both 100%). The magnitude of difference between standard and adjusted estimates varied depending on specificity and sensitivity assumptions. Specificity had the greatest impact on the magnitude of bias. CONCLUSIONS: Scientists should be aware of the impact of misclassification on incidence estimates. Appropriate study design, proper selection of the diagnostic test, and adjustment for misclassification probabilities in the analysis is necessary to obtain the most accurate incidence estimates.


Subject(s)
Hepatitis C/epidemiology , Pregnancy Complications, Infectious/epidemiology , Bias , Confidence Intervals , Female , Hepacivirus , Hepatitis C/virology , Humans , Incidence , Likelihood Functions , Models, Statistical , Pregnancy , Pregnancy Complications, Infectious/virology , Sensitivity and Specificity
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