Imperial College London

Dr Mikaela Smit

Faculty of MedicineSchool of Public Health

Honorary Research Fellow







47 Praed StreetSt Mary's Campus





Publication Type

12 results found

Smit M, Perez-Guzman PN, Mutai KK, Cassidy R, Kibachio J, Kilonzo N, Hallett TBet al., 2019, Mapping the current and future non-communicable disease burden in Kenya by HIV status: a modelling study., Clin Infect Dis

BACKGROUND: The non-communicable disease (NCD) burden in Kenya is not well characterised, despite estimates needed to identify future health priorities. We aim to quantify current and future NCD burden in Kenya by HIV status. METHODS: Original systematic reviews (SRs) and meta-analyses of prevalence/incidence of cardiovascular disease (CVD), chronic kidney disease, depression, diabetes, high total cholesterol, hypertension, human papillomavirus infection and related pre-cancerous stages in Kenya were carried out. An individual-based model was developed, simulating births, deaths, HIV-disease and treatment, aforementioned NCDs and cancers. The model was parameterised using SR, epidemiological national and regional surveillance data. NCD burden was quantified for 2018-2035 by HIV status amongst adults. FINDINGS: SRs identified prevalence/incidence data for each NCD, except ischemic heart disease. The model estimates that 51% of Kenyan adults currently suffer from ≥1 NCD, with a higher burden in People Living with HIV (PLHIV) compared to HIV-negative (62% versus 51%), driven by their higher age profile and partly by HIV-related risk for NCDs. Hypertension and high total cholesterol are the main NCD drivers (adult prevalence of 20·5% (5·3 million) and 9·0% (2·3 million)), with CVD and cancers the main causes of death. The burden is projected to increase by 2035 (56% in HIV-negative; 71% in PLHIV), with population growth doubling the number of people needing services (15·4 million to 28·1 million) by 2035. CONCLUSIONS: NCD services will need to be expanded in Kenya. Guidelines in Kenya already support provision of these amongst both the general and HIV-positive population, however coverage remains low.

Journal article

Smit M, Olney J, Ford NP, Vitoria M, Gregson S, Vassall A, Hallett TBet al., 2018, The growing burden of non-communicable disease among persons living with HIV in Zimbabwe, AIDS, Vol: 32, Pages: 773-782, ISSN: 0269-9370

Objectives:We aim to characterize the future noncommunicable disease (NCD)burden in Zimbabwe to identify future health system priorities.Methods:We developed an individual-based multidisease model for Zimbabwe,simulating births, deaths, infection with HIV and progression and key NCD [asthma,chronic kidney disease (CKD), depression, diabetes, hypertension, stroke, breast,cervical, colorectal, liver, oesophageal, prostate and all other cancers]. The modelwas parameterized using national and regional surveillance and epidemiological data.Demographic and NCD burden projections were generated for 2015 to 2035.Results:The model predicts that mean age of PLHIV will increase from 31 to 45 yearsbetween 2015 and 2035 (compared with 20 –26 in uninfected individuals). Conse-quently, the proportion suffering from at least one key NCD in 2035 will increase by26% in PLHIV and 6% in uninfected. Adult PLHIV will be twice as likely to suffer from atleast one key NCD in 2035 compared with uninfected adults; with 15.2% of all keyNCDs diagnosed in adult PLHIV, whereas contributing only 5% of the Zimbabweanpopulation. The most prevalent NCDs will be hypertension, CKD, depression andcancers. This demographic and disease shift in PLHIV is mainly because of reductions inincidence and the success of ART scale-up leading to longer life expectancy, and to alesser extent, the cumulative exposure to HIV and ART.Conclusion:NCD services will need to be expanded in Zimbabwe. They will need tobe integrated into HIV care programmes, although the growing NCD burden amongstuninfected individuals presenting opportunities for additional services developedwithin HIV care to benefit HIV-negative persons.

Journal article

Smit M, Cassidy R, Cozzi-Lepri A, Quiros-Roldan E, Girardi E, Mammone A, Antinori A, Saracino A, Bai F, Rusconi S, Magnani G, Castelli F, Prisculla H, d'Arminio Monforte A, Hallett TBet al., 2017, Projections of Non-Communicable Disease and Health Care Costs Among HIV-Positive Persons in Italy and the U.S.A: A Modelling Study, PLoS ONE, Vol: 12, ISSN: 1932-6203

BackgroundCountry-specific forecasts of the growing non-communicable disease (NCD) burden in ageing HIV-positive patients will be key to guide future HIV policies. We provided the first national forecasts for Italy and the Unites States of America (USA) and quantified direct cost of caring for these increasingly complex patients.Methods and SettingWe adapted an individual-based model of ageing HIV-positive patients to Italy and the USA, which followed patients on HIV-treatment as they aged and developed NCDs (chronic kidney disease, diabetes, dyslipidaemia, hypertension, non-AIDS malignancies, myocardial infarctions and strokes). The models were parameterised using data on 7,469 HIV-positive patients from the Italian Cohort Naïve to Antiretrovirals Foundation Study and 3,748 commercially-insured patients in the USA and extrapolated to national level using national surveillance data.ResultsThe model predicted that mean age of HIV-positive patients will increase from 46 to 59 in Italy and from 49 to 58 in the USA in 2015–2035. The proportion of patients in Italy and the USA diagnosed with ≥1 NCD is estimated to increase from 64% and 71% in 2015 to 89% and 89% by 2035, respectively, driven by moderate cardiovascular disease (CVD) (hypertension and dyslipidaemia), diabetes and malignancies in both countries. NCD treatment costs as a proportion of total direct HIV costs will increase from 11% to 23% in Italy and from 40% to 56% in the USA in 2015–2035.ConclusionsHIV patient profile in Italy and the USA is shifting to older patients diagnosed with multiple co-morbidity. This will increase NCD treatment costs and require multi-disciplinary patient management.

Journal article

Smit M, van Zoest RA, Nichols BE, Vaartjes I, Smit C, van der Vallk M, van Sighem A, Wit FW, Hallett TB, Reiss Pet al., 2017, Cardiovascular disease prevention policy in HIV: recommendations from a modelling study, Clinical Infectious Diseases, Vol: 66, Pages: 743-750, ISSN: 1058-4838

BackgroundCardiovascular disease (CVD) is expected to contribute a large noncommunicable disease burden among human immunodeficiency virus (HIV)–infected people. We quantify the impact of prevention interventions on annual CVD burden and costs among HIV-infected people in the Netherlands.MethodsWe constructed an individual-based model of CVD in HIV-infected people using national ATHENA (AIDS Therapy Evaluation in The Netherlands) cohort data on 8791 patients on combination antiretroviral therapy (cART). The model follows patients as they age, develop CVD (by incorporating a CVD risk equation), and start cardiovascular medication. Four prevention interventions were evaluated: (1) increasing the rate of earlier HIV diagnosis and treatment; (2) avoiding use of cART with increased CVD risk; (3) smoking cessation; and (4) intensified monitoring and drug treatment of hypertension and dyslipidemia, quantifying annual number of averted CVDs and costs.ResultsThe model predicts that annual CVD incidence and costs will increase by 55% and 36% between 2015 and 2030. Traditional prevention interventions (ie, smoking cessation and intensified monitoring and treatment of hypertension and dyslipidemia) will avert the largest number of annual CVD cases (13.1% and 20.0%) compared with HIV-related interventions—that is, earlier HIV diagnosis and treatment and avoiding cART with increased CVD risk (0.8% and 3.7%, respectively)—as well as reduce cumulative CVD-related costs. Targeting high-risk patients could avert the majority of events and costs.ConclusionsTraditional CVD prevention interventions can maximize cardiovascular health and defray future costs, particularly if targeting high-risk patients. Quantifying additional public health benefits, beyond CVD, is likely to provide further evidence for policy development.

Journal article

Smit M, Cassidy R, Cozzi-Lepri A, Girardi E, Mammone A, Antinori A, Angarano G, Bai F, Rusconi S, Magnani G, Monforte AD, Hallett Tet al., 2016, Quantifying the future clinical burden of an ageing HIV-positive population in Italy: a mathematical modelling study, International Congress of Drug Therapy in HIV Infection, Publisher: JOHN WILEY & SONS LTD

Conference paper

Smit M, Cassidy R, Hallett T, 2016, Quantifying the future clinical burden of an ageing HIV-positive population in the USA: a mathematical modelling, Publisher: JOHN WILEY & SONS LTD

Conference paper

Althoff KN, Smit M, Reiss P, Justice ACet al., 2016, HIV and ageing: improving quantity and quality of life, Current Opinions in HIV & AIDS, Vol: 11, Pages: 527-536, ISSN: 1746-630X

Purpose of reviewEvidence-based strategies are needed to address the growing complexity of care of those ageing with HIVso that as life expectancy is extended, quality of life is also enhanced.Recent findingsModifiable contributing factors to the quantity and quality of life in adults ageing with HIV include: burdenof harmful health behaviours, injury from HIV infection, HIV treatment toxicity and general burden of ageassociatedcomorbidities. In turn, these factors contribute to geriatric syndromes including multimorbidityand polypharmacy, physiologic frailty, falls and fragility fractures and cognitive dysfunction, which furthercompromise the quality of life long before they lead to mortality.SummaryViral suppression of HIV with combination antiviral therapy has led to increasing longevity but has notenabled a complete return to health among ageing HIV-infected individuals (HIVþ). As adults age withHIV, the role of HIV itself and associated inflammation, effects of exposure to antiretroviral agents, the highprevalence of modifiable risk factors for age-associated conditions (e.g. smoking), and the effects of otherviral coinfections are all influencing the health trajectory of persons ageing with HIV. We must move fromthe simplistic notion of HIV becoming a ‘chronic controllable illness’ to understanding the continuallyevolving ‘treated’ history of HIV infection with the burden of age-associated conditions and geriatricsyndromes in the context of an altered and ageing immune system.

Journal article

Smit M, Hallett T, 2016, Respiratory co-morbidities in people with HIV, Lancet Infectious Diseases, Vol: 16, Pages: 152-152, ISSN: 1473-3099

Journal article

Smit M, Brinkman K, Geerlings S, Smit C, Thyagarajan K, van Sighem A, de Wolf F, Hallett TBet al., 2015, Future challenges for clinical care of an ageing population infected with HIV: a modelling study, Lancet Infectious Diseases, Vol: 15, Pages: 810-818, ISSN: 1473-3099

Background The population infected with HIV is getting older and these people will increasingly develop age-relatednon-communicable diseases (NCDs). We aimed to quantify the scale of the change and the implications for HIV carein the Netherlands in the future.Methods We constructed an individual-based model of the ageing HIV-infected population, which followed patientson HIV treatment as they age, develop NCDs—including cardiovascular disease (hypertension, hypercholesterolaemia,myocardial infarctions, and strokes), diabetes, chronic kidney disease, osteoporosis, and non-AIDS malignancies—and start co-medication for these diseases. The model was parameterised by use of data for 10 278 patients from thenational Dutch ATHENA cohort between 1996 and 2010. We made projections up to 2030.Findings Our model suggests that the median age of HIV-infected patients on combination antiretroviral therapy(ART) will increase from 43·9 years in 2010 to 56·6 in 2030, with the proportion of HIV-infected patients aged50 years or older increasing from 28% in 2010 to 73% in 2030. In 2030, we predict that 84% of HIV-infected patientswill have at least one NCD, up from 29% in 2010, with 28% of HIV-infected patients in 2030 having three or moreNCDs. 54% of HIV-infected patients will be prescribed co-medications in 2030, compared with 13% in 2010, with20% taking three or more co-medications. Most of this change will be driven by increasing prevalence ofcardiovascular disease and associated drugs. Because of contraindications and drug–drug interactions, in 2030, 40%of patients could have complications with the currently recommended fi rst-line HIV regimens.Interpretation The profi le of patients in the Netherlands infected with HIV is changing, with increasing numbers ofolder patients with multiple morbidities. These changes mean that, in the near future, HIV care will increasingly need todraw on a wide range of medical disciplines, in addition to evidence-bas

Journal article

Smit M, Smit C, Geerlings S, Gras L, Brinkman K, Hallett TB, de Wolf Fet al., 2013, Changes in First-Line cART Regimens and Short-Term Clinical Outcome between 1996 and 2010 in The Netherlands, PLOS One, Vol: 8, ISSN: 1932-6203

Objectives: Document progress in HIV-treatment in the Netherlands since 1996 by reviewing changing patterns of cART useand relating those to trends in patients’ short-term clinical outcomes between 1996 and 2010.Design and Methods: 1996–2010 data from 10,278 patients in the Dutch ATHENA national observational cohort wereanalysed. The annual number of patients starting a type of regimen was quantified. Trends in the following outcomes weredescribed: i) recovery of 150 CD4 cells/mm3 within 12 months of starting cART; ii) achieving viral load (VL) suppression#1,000 copies/ml within 12 months of starting cART; iii) switching from first-line to second-line regimen within three yearsof starting treatment; and iv) all-cause mortality rate per 100 person-years within three years of starting treatment.Results: Between 1996 and 2010, first-line regimens changed from lamivudine/zidovudine-based or lamivudine/stavudinebasedregimens with unboosted-PIs to tenofovir with either emtricitabine or lamivudine with NNRTIs. Mortality rates did notchange significantly over time. VL suppression and CD4 recovery improved over time, and the incidence of switching due tovirological failure and toxicity more than halved between 1996 and 2010. These effects appear to be related to the use ofnew regimens rather than improvements in clinical care.Conclusion: The use of first-line cART in the Netherlands closely follows changes in guidelines, to the benefit of patients.While there was no significant improvement in mortality, newer drugs with better tolerability and simpler dosing resulted inimproved immunological and virological recovery and reduced incidences of switching due to toxicity and virologicalfailure.

Journal article

Smit M, Smit C, Cremin I, Garnett GP, Hallett T, de Wolf Fet al., 2012, Could better tolerated HIV drug regimens improve patient outcome?, AIDS, Vol: 26, Pages: 1953-1959, ISSN: 0269-9370

Journal article

Smit M, Smit C, Cremin I, Hallett T, De Wolf F, Garnett GPet al., 2011, New Drugs Trageting Toxicities Have HIghest Hope of Impacting Patients Prognosis, International Society for Sexually Transmitted Diseases Research

Conference paper

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