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Ware LJ, Charlton K, Schutte AE, Cockeran M, Naidoo N, Kowal P. Associations between dietary salt, potassium and blood pressure in South African adults: WHO SAGE Wave 2 Salt & Tobacco. Nutr Metab Cardiovasc Dis 2017; 27:784-791. [PMID: 28800936 DOI: 10.1016/j.numecd.2017.06.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/14/2017] [Accepted: 06/26/2017] [Indexed: 11/18/2022]
Abstract
BACKGROUND & AIMS In June 2016, South Africa implemented legislation mandating maximum sodium levels in a range of processed foods with a goal of reducing population salt intake and disease burden from hypertension. Our aim was to explore the relationship between salt and blood pressure (BP) in a subsample of the World Health Organization Study on global AGEing and adult health (SAGE) Wave 2 before implementation of legislation in South Africa. METHODS & RESULTS Blood pressure (BP) was measured in triplicate (n = 2722; median age 56 years; 33% male) and 24-h urine collected in a nested subsample (n = 526) for sodium, potassium and creatinine analysis. Hypertension prevalence was 55% in older adults (50-plus years) and 28% in younger adults (18-49 years). Median salt intake (6.8 g/day) was higher in younger than older adults (8.6 g vs 6.1 g/day; p < 0.001), and in urban compared to rural populations (7.0 g vs 6.0 g/day; p = 0.033). Overall, 69% of participants had salt intakes above 5 g/day. Potassium intakes were generally low (median 35 mmol/day) with significantly lower intakes in rural areas and older adults. Overall, 91% of adults failed to meet the daily potassium recommendation of 90 mmol/d. Salt intakes above 5 g/day, and to a greater extent, a dietary sodium-to-potassium (Na:K) ratio above 2 mmol/mmol, were associated with significantly steeper regression slopes of BP with age. CONCLUSION These preliminary results indicate that high dietary Na:K ratio may lead to a greater increase in BP and hypertension risk with age. Interventions to increase potassium intakes alongside sodium reduction initiatives may be warranted.
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Comparative Study |
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Uys M, Shahid M, Sallinen J, Dreyer W, Cockeran M, Harvey BH. The α2C-adrenoceptor antagonist, ORM-10921, has antipsychotic-like effects in social isolation reared rats and bolsters the response to haloperidol. Prog Neuropsychopharmacol Biol Psychiatry 2016; 71:108-16. [PMID: 27381554 DOI: 10.1016/j.pnpbp.2016.07.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 06/28/2016] [Accepted: 07/01/2016] [Indexed: 02/04/2023]
Abstract
Early studies suggest that selective α2C-adrenoceptor (AR)-antagonism has anti-psychotic-like and pro-cognitive properties. However, this has not been demonstrated in an animal model of schizophrenia with a neurodevelopmental construct. The beneficial effects of clozapine in refractory schizophrenia and associated cognitive deficits have, among others, been associated with its α2C-AR modulating activity. Altered brain-derived neurotrophic factor (BDNF) has been linked to schizophrenia and cognitive deficits. We investigated whether the α2C-AR antagonist, ORM-10921, could modulate sensorimotor gating and cognitive deficits, as well as alter striatal BDNF levels in the social isolation reared (SIR) model of schizophrenia, comparing its effects to clozapine and the typical antipsychotic, haloperidol, the latter being devoid of α2C-AR-activity. Moreover, the ability of ORM-10921 to augment the effects of haloperidol on the above parameters was also investigated. Animals received subcutaneous injection of either ORM-10921 (0.01mg/kg), clozapine (5mg/kg), haloperidol (0.2mg/kg), haloperidol (0.2mg/kg)+ORM-10921 (0.01mg/kg) or vehicle once daily for 14days, followed by assessment of novel object recognition (NOR), prepulse inhibition (PPI) of startle response and striatal BDNF levels. SIR significantly attenuated NOR memory as well as PPI, and reduced striatal BDNF levels vs. social controls. Clozapine, ORM-10921 and haloperidol+ORM-10921, but not haloperidol alone, significantly improved SIR-associated deficits in PPI and NOR, with ORM-10921 also significantly improving PPI deficits vs. haloperidol-treated SIR animals. Haloperidol+ORM-10921 significantly reversed reduced striatal BDNF levels in SIR rats. α2C-AR-antagonism improves deficits in cognition and sensorimotor gating in a neurodevelopmental animal model of schizophrenia and bolsters the effects of a typical antipsychotic, supporting a therapeutic role for α2C-AR-antagonism in schizophrenia.
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Charlton K, Ware LJ, Baumgartner J, Cockeran M, Schutte AE, Naidoo N, Kowal P. How will South Africa's mandatory salt reduction policy affect its salt iodisation programme? A cross-sectional analysis from the WHO-SAGE Wave 2 Salt & Tobacco study. BMJ Open 2018; 8:e020404. [PMID: 29602855 PMCID: PMC5884349 DOI: 10.1136/bmjopen-2017-020404] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 02/05/2018] [Accepted: 02/09/2018] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE The WHO's global targets for non-communicable disease reduction recommend consumption of<5 g salt/day. In 2016, South Africa was the first country to legislate maximum salt levels in processed foods. South Africa's salt iodisation fortification programme has successfully addressed iodine deficiency but information is dated. Simultaneous monitoring of sodium reduction and iodine status is required to ensure compatibility of the two public health interventions. DESIGN/SETTING/PARTICIPANTS A nested cohort design within WHO's 2015 Study on global AGEing and adult health (n=2887) including individuals from households across South Africa. Randomly selected adults (n=875) provided 24-hour and spot urine samples for sodium and iodine concentration analysis (the primary and secondary outcome measures, respectively). Median 24-hour urinary iodine excretion (UIE) and spot urinary iodine concentrations (UIC) were compared by salt intakes of <5g/day, 5-9g/dayand >9 g/day. RESULTS Median daily sodium excretion was equivalent to 6.3 g salt/day (range 1-43 g/day); 35% had urinary sodium excretion values within the desirable range (<5 g salt/day), 37% had high values (5-9 g salt/day) and 28% had very high values (>9 g salt/day). Median UIC was 130 µg/L (IQR=58-202), indicating population iodine sufficiency (≥100 µg/L). Both UIC and UIE differed across salt intake categories (p<0.001) and were positively correlated with estimated salt intake (r=0.166 and 0.552, respectively; both p<0.001). Participants with salt intakes of <5 g/day were not meeting the Estimated Average Requirement for iodine intake (95 µg/day). CONCLUSIONS In a nationally representative sample of South African adults, the association between indicators of population iodine status (UIC and UIE) and salt intake, estimated using 24-hour urinary sodium excretion, indicate that low salt intakes may compromise adequacy of iodine intakes in a country with mandatory iodisation of table salt. The iodine status of populations undergoing salt reduction strategies needs to be closely monitored to prevent re-emergence of iodine deficiency.
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Research Support, N.I.H., Extramural |
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Griffiths ME, Malan L, Delport R, Cockeran M, Reimann M. Troponin T release is associated with silent myocardial ischaemia in black men: The SABPA Study. Eur J Prev Cardiol 2017; 24:942-950. [PMID: 28195519 DOI: 10.1177/2047487317694465] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background High sensitivity cardiac troponin T (hs-cTnT) is a validated marker of myocardial damage and may reflect the degree of silent myocardial ischaemia (SMI) and ventricular strain. Our aim was to compare hs-cTnT levels in black and white South Africans taking SMI into consideration. We further explored the capability of hs-cTnT to predict the presence of compensatory systolic hypertension in this South African cohort. Methods A bi-ethnic sex cohort ( n = 404) with similar socioeconomic status (198 black participants and 206 white participants, aged 20-65 years) participated in this target population study where 24 h ambulatory blood pressure, electrocardiogram and overnight fasting cardiometabolic variables were measured. Results Hypertension, higher glycated haemoglobin levels and more frequent and longer SMI events were observed more often in the black participants. Multivariate linear regression analysis showed positive associations between SMI events [Adj. R2 = 0.19; β 0.35 (0.08-0.62); p < 0.01], SMI event maximum duration [Adj. R2 = 0.17, β 0.43 (0.16-0.70), p < 0.01], SMI total duration [Adj. R2 = 0.12; β 0.37 (0.10; 0.65), p = 0.05] and hs-cTnT in black males only.] A lower hs-cTnT cut-point ≥4.2 pg/ml for 24 h systolic hypertension was predicted in the black participants compared with ≥5.6 pg/ml in the white participants (area under the curve 0.66-67 (95% CI: 0.57-0.75), p < 0.001) with a respective sensitivity/specificity of 64/68% and 61/71%. Conclusions hs-cTnT may be a potential marker of SMI in the prediction of systolic blood pressure increases, as well as clusters of risk factors for cardiovascular disease. Ethnic- and possibly sex-specific references values for hs-cTnT should be considered for risk stratification.
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Comparative Study |
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van der Vaart L, Linde B, Cockeran M. The state of the psychological contract and employees’ intention to leave: The mediating role of employee well-being. SOUTH AFRICAN JOURNAL OF PSYCHOLOGY 2013. [DOI: 10.1177/0081246313494154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Changes in the work environment can influence employees’ perception of the employment relationship, their psychological contracts, and consequently, their work-related attitudes and behaviour. The study aimed to demonstrate the mechanism through which the state of employees’ psychological contract impacts employees’ intention to leave employment and the role of employee well-being as a mediator. Cross-sectional data were obtained from employees representing various organisations ( N = 246). Structural equation modelling demonstrated that employee well-being mediates the relationship between the state of the psychological contract and an employee’s intention to leave the organisation. The study stresses the importance of designing individual-level interventions to enhance well-being in the workplace, which should form part of the retention strategy of any organisation.
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Mouton M, Harvey BH, Cockeran M, Brink CB. The long-term effects of methamphetamine exposure during pre-adolescence on depressive-like behaviour in a genetic animal model of depression. Metab Brain Dis 2016; 31:63-74. [PMID: 26581673 DOI: 10.1007/s11011-015-9765-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 11/11/2015] [Indexed: 01/01/2023]
Abstract
Methamphetamine (METH) is a psychostimulant and drug of abuse, commonly used early in life, including in childhood and adolescence. Adverse effects include psychosis, anxiety and mood disorders, as well as increased risk of developing a mental disorder later in life. The current study investigated the long-term effects of chronic METH exposure during pre-adolescence in stress-sensitive Flinders Sensitive Line (FSL) rats (genetic model of depression) and control Flinders Resistant Line (FRL) rats. METH or vehicle control was administered twice daily from post-natal day 19 (PostND19) to PostND34, followed by behavioural testing at either PostND35 (early effects) or long-lasting after withdrawal at PostND60 (early adulthood). Animals were evaluated for depressive-like behaviour, locomotor activity, social interaction and object recognition memory. METH reduced depressive-like behaviour in both FSL and FRL rats at PostND35, but enhanced this behaviour at PostND60. METH also reduced locomotor activity on PostND35 in both FSL and FRL rats, but without effect at PostND60. Furthermore, METH significantly lowered social interaction behaviour (staying together) in both FRL and FSL rats at PostND35 and PostND60, whereas self-grooming time was significantly reduced only at PostND35. METH treatment enhanced exploration of the familiar vs. novel object in the novel object recognition test (nORT) in FSL and FRL rats on PostND35 and PostND60, indicative of reduced cognitive performance. Thus, early-life METH exposure induce social and cognitive deficits. Lastly, early-life exposure to METH may result in acute antidepressant-like effects immediately after chronic exposure, whereas long-term effects after withdrawal are depressogenic. Data also supports a role for genetic predisposition as with FSL rats.
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Oosthuizen W, Malan L, Scheepers JD, Cockeran M, Malan NT. The defense response and alcohol intake: A coronary artery disease risk? The SABPA Study. Clin Exp Hypertens 2016; 38:526-32. [PMID: 27399032 DOI: 10.3109/10641963.2016.1163372] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Chikowore T, Cockeran M, Conradie KR, van Zyl T. C679X loss-of-function PCSK9 variant lowers fasting glucose levels in a black South African population: A longitudinal study. Diabetes Res Clin Pract 2018; 144:279-285. [PMID: 30227170 DOI: 10.1016/j.diabres.2018.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 08/27/2018] [Accepted: 09/13/2018] [Indexed: 12/21/2022]
Abstract
AIMS To determine the longitudinal association of the loss-of-function (LOF) PCSK9 variants (C679X and A443T), proxies of PCSK9 inhibitor drugs, with LDL-C, fasting glucose and glycated hemoglobin. METHODS We conducted a five year, longitudinal study, nested within the Prospective Urban and Rural Epidemiology study, among 737 apparently healthy, male and female black South Africans of the North West province. Genotyping of the C679X and A443T PCSK9 variants was achieved using Taqman assays from Applied Biosystems. Generalized estimating equations were used to determine longitudinal association of the A443T and C679X PCSK9 variants with LDL-C, fasting glucose and glycated hemoglobin. RESULTS C679X and A443T variant carriers were associated with significant reductions in LDL-C of -0.98(-1.29, -0.67) mmol/L; p < 0.001) and -0.39(-0.57, -0.20) mmol/L; p < 0.001) respectively, compared to the non-carriers. Only C679X variant was independently associated with reductions in fasting glucose of -0.37 (-0.61, -0.13) mmol/L; p = 0.002) compared to non-carriers. However, the association of the selected variants with glycated hemoglobin were not significant. C679X and A443T carriers were associated with -0.07 (-0.23, 0.09) %; p = 0.400), 0.05 (-0.13, 0.22) %; p = 0.599) of glycated haemoglobin respectively. CONCLUSION Our results indicated that carriers of A443T and C679X variants exhibit sustained low LDL-C levels over 5 years and have varied effects on T2D biomarkers compared to non-carriers.
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Charlton KE, Ware LJ, Baumgartner J, Cockeran M, Schutte AE, Naidoo N, Kowal P. Iodine Status Assessment in South African Adults According to Spot Urinary Iodine Concentrations, Prediction Equations, and Measured 24-h Iodine Excretion. Nutrients 2018; 10:E736. [PMID: 29880734 PMCID: PMC6024758 DOI: 10.3390/nu10060736] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 12/15/2022] Open
Abstract
The iodine status of populations is conventionally assessed using spot urinary samples to obtain a median urinary iodine concentration (UIC) value, which is assessed against standard reference cut-offs. The assumption that spot UIC reflects daily iodine intake may be flawed because of high day-to-day variability and variable urinary volume outputs. This study aimed to compare iodine status in a sample of South African adults when determined by different approaches using a spot urine sample (median UIC (MUIC), predicted 24 h urinary iodine excretion (PrUIE) using different prediction equations) against measured 24 h urinary iodine excretion (mUIE). Both 24 h and spot urine samples were collected in a subsample of participants (n = 457; median age 55 year; range 18⁻90 year) in the World Health Organization Study on global AGEing and adult health (SAGE) Wave 2 in South Africa, in 2015. Kawasaki, Tanaka, and Mage equations were applied to assess PrUIE from predicted urinary creatinine (PrCr) and spot UIC values. Adequacy of iodine intake was assessed by comparing PrUIE and mUIE to the Estimated Average Requirement of 95 µg/day, while the MUIC cut-off was.
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Comparative Study |
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Schutte CE, Malan L, Scheepers JD, Oosthuizen W, Cockeran M, Malan NT. Cortisol:brain-derived neurotrophic factor ratio associated with silent ischaemia in a black male cohort: the SA BPA study. Cardiovasc J Afr 2017; 27:387-391. [PMID: 27966001 PMCID: PMC5408496 DOI: 10.5830/cvja-2016-065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 05/29/2016] [Indexed: 11/24/2022] Open
Abstract
Aim Emotional distress has been associated with cardiovascular disease (CVD) in Africans. Cortisol and brain-derived neurotrophic factor (BDNF), as markers of emotional distress, increase cardiometabolic risk. We therefore aimed to investigate associations between cardiometabolic risk markers and the cortisol-to-BDNF ratio (cortisol:BDNF). Methods A cross-sectional study included a bi-ethnic gender cohort (n = 406) aged 44.7 ± 9.52 years. Ambulatory blood pressure (ABPM), ECG, fasting serum cortisol and BDNF levels and cardiometabolic risk markers were obtained. Results Africans had increased incidence of hyperglycaemia and 24-hour silent ischaemic events, and elevated 24-hour blood pressure (BP) and cortisol:BDNF ratios compared to Caucasians. Forward stepwise linear regression analysis underscored a similar trend with associations between hyperglycaemia, 24-hour BP [Adj R2 0.21–0.29; β 0.23 (0.1–0.4); p = 0.01], silent ischaemia [Adj R2 0.22; β 0.40 (0.2–0.6); p < 0.01] and cortisol:BDNF levels in Africans, mostly in the men. Conclusion Attenuated cortisol levels in this group may be indicative of emotional distress and if chronic, drive the cortisol:BDNF ratio to desensitise BDNF. Desensitised cortisol:BDNF may sustain cardiometabolic risk and induce neurodegeneration in African men via silent ischaemia. Compensatory increases in blood pressure to increase perfusion and maintain homeostasis may increase coronary artery disease risk.
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Jansen van Vuren E, Malan L, Cockeran M, Scheepers JD, Oosthuizen W, Malan NT. Fibrosis and coronary perfusion - a cardiovascular disease risk in an African male cohort: The SABPA study. Clin Exp Hypertens 2016; 38:482-8. [PMID: 27380493 DOI: 10.3109/10641963.2016.1151524] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Low-grade inflammation has been correlated with risk factors of cardiovascular diseases (CVD). Whether the pro-inflammatory and thrombotic ratio (fibrosis) may contribute to CVD is not known. We therefore aimed to assess whether Cornell Product left ventricular hypertrophy (LVH) is associated with fibrosis and coronary perfusion (silent ischemia) in a bi-ethnic male cohort from South Africa. A cross sectional study was conducted including 165 African and Caucasian men between the ages of 20-65. Fasting blood samples were obtained to measure fibrinogen, C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor (TNF-α). Ambulatory blood pressure, ECG and 12 lead ECG measures were obtained to determine silent ischemic events (ST events) and LVH, respectively. Africans revealed more silent ischemia, higher 24 h blood pressure, inflammatory, coagulation as well as fibrosis levels than Caucasians. In a low-grade inflammatory state (CRP > 3 mg/l), Africans revealed higher fibrosis (p ≤ 0.01) values, but lower IL-6 and TNF-α values than Caucasians. Linear regression analyses in several models demonstrated positive associations between silent ischemia and fibrosis [Adj. R(2) 0.23; ß 0.35 (95% CI 0.13, 0.58), p ≤ 0.01]. In a low-grade inflammatory state (CRP>3mg/l), fibrinogen predicted AV-block in African men [OR 3.38 (95% CI 2.24, 4.53); p = 0.04]. Low-grade inflammation may induce AV-block through mechanisms involving fibrosis and ischemia to increase the burden on the heart in African men.
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Greffrath WP, du Plessis JM, Viljoen M, Cockeran M. Hypertriglyceridaemia and the risk of pancreatitis six months post lopinavir/ritonavir initiation. South Afr J HIV Med 2018; 19:766. [PMID: 30167336 PMCID: PMC6111571 DOI: 10.4102/sajhivmed.v19i1.766] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 12/20/2017] [Indexed: 01/27/2023] Open
Abstract
Background Hypertriglyceridaemia (HTG) is an important risk factor for pancreatitis and cardiovascular disease (CVD), depending on severity. Hypertriglyceridaemia is common in human immunodeficiency virus (HIV) infection and is also a common complication of lopinavir/ritonavir (LPV/r). Objectives To evaluate the risk of pancreatitis associated with HTG in patients six months post initiation of LPV/r-based therapy in a regional public hospital. Methods Triglyceride (TG), serum amylase (s-amylase) and CD4+ count values were retrospectively investigated six months post LPV/r-based initiation. Age, gender, previous antiretroviral regimen and period since HIV diagnosis were also recorded. Results The final sample consisted of 194 patients, 50 males and 144 females; mean (± standard deviation [s.d.]) age was 39.52 (± 9.98) years, and the mean (± s.d.) period since HIV diagnosis was 91.32 (± 25.18) months. Normal TG levels (< 1.70 mmol/L) were detected in only 55% of patients and the rest presented with some degree of HTG. The mean (± s.d.) TG for the entire sample was elevated at 1.94 (± 1.30) mmol/L with the mean (± s.d.) of the males at 2.36 (± 1.74) – statistically higher compared to the females at 1.79 (± 1.08) mmol/L (p = 0.034). No cases of pancreatitis were recorded and the time since HIV diagnosis did not indicate any statistically significant differences in the means of the TG, serum amylase or CD4 count values. Conclusion Triglyceride levels were not substantially elevated to induce pancreatitis at six months post initiation of LPV/r, but were elevated above the accepted upper normal limit of 1.70 mmol/L which may have implications for cardiovascular risk.
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Scheepers JDW, Malan L, De Kock A, Malan NT, Cockeran M, von Känel R. Ethnic disparity in defensive coping endothelial responses: The SABPA study. Physiol Behav 2015; 147:306-12. [DOI: 10.1016/j.physbeh.2015.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/25/2015] [Accepted: 05/04/2015] [Indexed: 12/28/2022]
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Olivier N, Burger J, Joubert R, Lubbe M, Naudé A, Cockeran M. Chronic disease list conditions in patients with rheumatoid arthritis in the private healthcare sector of South Africa. Rheumatol Int 2017; 38:837-844. [PMID: 29234875 DOI: 10.1007/s00296-017-3907-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/05/2017] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Little is known about the burden of rheumatoid arthritis (RA) in South Africa. The aim of this study was to establish the prevalence of RA and coexisting chronic disease list (CDL) conditions in the private health sector of South Africa. METHODS A retrospective, cross-sectional analysis was performed on medicine claims data from 1 January 2014 to 31 December 2014 to establish the prevalence of RA. The cohort of RA patients was then divided into those with and those without CDL conditions, to determine the number and type of CDL conditions per patient, stratified by age group and gender. RESULTS A total 4352 (0.5%) patients had RA, of whom 69.3% (3016) presented with CDL conditions. Patients had a median age of 61.31 years (3.38; 98.51), and 74.8% were female. Patients with CDL conditions were older than those patients without (p < 0.001; Cohen's d = 0.674). Gender had no influence on the presence of CDL conditions (p = 0.456). Men had relatively higher odds for hyperlipidemia (OR 1.83; CI 1.33-2.51; p < 0.001) and lower odds for asthma (OR 0.83; CI 0.48-1.42; p = 0.490) than women. In combination with hyperlipidemia, the odds for asthma were reversed and strongly increased (OR 6.74; CI 2.07-21.93; p = 0.002). The odds for men having concomitant hyperlipidemia, hypertension, type 2 diabetes mellitus and hypothyroidism were insignificant and low (OR 0.40; CI 0.16-1.02; p = 0.055); however, in the absence of hypothyroidism, the odds increased to 3.26 (CI 2.25-4.71; p < 0.001). CONCLUSION Hypothyroidism was an important discriminating factor for comorbidity in men with RA. This study may contribute to the body of evidence about the burden of RA and coexisting chronic conditions in South Africa.
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Cockeran M, Meintanis SG, Allison JS. Goodness-of-fit tests in the Cox proportional hazards model. COMMUN STAT-SIMUL C 2019. [DOI: 10.1080/03610918.2019.1639738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Mwango S, Carboo J, Ellis C, Cockeran M, Mels CMC, Kruger HS. The association between serum vitamin D and body composition in South African HIV-infected women. South Afr J HIV Med 2021; 22:1284. [PMID: 34691771 PMCID: PMC8517828 DOI: 10.4102/sajhivmed.v22i1.1284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/12/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND HIV and antiretroviral therapy (ART) alter vitamin D metabolism, and may be associated with bone loss. OBJECTIVES The aim of this study was to determine the association between serum 25-hydroxyvitamin D (25(OH)D) and body composition in postmenopausal South African women living with HIV and on ART. METHOD In this 2-year longitudinal study on 120 women conducted in the North West province of South Africa, serum 25(OH)D concentration, bone mineral density (BMD) at three sites, lean mass and percentage of body fat (%BF) were measured by dual-energy X-ray absorptiometry (DXA). Multivariable linear mixed models were used to assess the association between serum 25(OH)D and body composition over 2 years. Linear mixed models were also used to determine the longitudinal association between lean mass, %BF and BMD. RESULTS Vitamin D deficiency and insufficiency increased from baseline (10.2% and 19.5%) to 11.5% and 37.5%, respectively, after 2 years. Serum 25(OH)D decreased significantly, however, with a small effect size of 0.39 (P = 0.001), whilst total BMD (effect size 0.03, P = 0.02) and left hip femoral neck (FN) BMD (effect size 0.06, P = 0.0001) had significant small increases, whereas total spine BMD did not change over the 2 years. Serum 25(OH)D had no association with any BMD outcomes. Lean mass had a stronger positive association with total spine and left FN BMD than %BF. CONCLUSION Serum 25(OH)D was not associated with any BMD outcomes. Maintenance of lean mass could be important in preventing bone loss in this vulnerable group; however, longer follow-up may be necessary to confirm the association.
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Jacobs K, Julyan M, Lubbe MS, Burger JR, Cockeran M. Medicine possession ratio as proxy for adherence to antiepileptic drugs: prevalence, associations, and cost implications. Patient Prefer Adherence 2016; 10:539-47. [PMID: 27110104 PMCID: PMC4835143 DOI: 10.2147/ppa.s98940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE To determine the adherence status to antiepileptic drugs (AEDs) among epilepsy patients; to observe the association between adherence status and age, sex, active ingredient prescribed, treatment period, and number of comorbidities; and to determine the effect of nonadherence on direct medicine treatment cost of AEDs. METHODS A retrospective study analyzing medicine claims data obtained from a South African pharmaceutical benefit management company was performed. Patients of all ages (N=19,168), who received more than one prescription for an AED, were observed from 2008 to 2013. The modified medicine possession ratio (MPRm) was used as proxy to determine the adherence status to AED treatment. The MPRm was considered acceptable (adherent) if the calculated value was ≥80%, but ≤110%, whereas an MPRm of <80% (unacceptably low) or >110% (unacceptably high) was considered nonadherent. Direct medicine treatment cost was calculated by summing the medical scheme contribution and patient co-payment associated with each AED prescription. RESULTS Only 55% of AEDs prescribed to 19,168 patients during the study period had an acceptable MPRm. MPRm categories depended on the treatment period (P>0.0001; Cramer's V=0.208) but were independent of sex (P<0.182; Cramer's V=0.009). Age group (P<0.0001; Cramer's V=0.067), active ingredient (P<0.0001; Cramer's V=0.071), and number of comor-bidities (P<0.0001; Cramer's V=0.050) were statistically but not practically significantly associated with MPRm categories. AEDs with an unacceptably high MPRm contributed to 3.74% (US$736,376.23) of the total direct cost of all AEDs included in the study, whereas those with an unacceptably low MPRm amounted to US$3,227,894.85 (16.38%). CONCLUSION Nonadherence to antiepileptic treatment is a major problem, encompassing ~20% of cost in our study. Adherence, however, is likely to improve with the treatment period. Further research is needed to determine the factors influencing epileptic patients' prescription refill adherence.
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Jacobs K, Julyan M, Lubbe MS, Burger JR, Cockeran M. Anti-epileptic prescribing patterns in the South African private health sector (2008–2013). S Afr Fam Pract (2004) 2016. [DOI: 10.1080/20786190.2016.1148337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Bothma E, Allison JS, Cockeran M, Visagie IJH. Characteristic function and Laplace transform‐based tests for exponentiality in the presence of random right censoring. Stat (Int Stat Inst) 2021. [DOI: 10.1002/sta4.394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Scheepers JDW, Malan L, de Kock A, Malan NT, Cockeran M, von Känel R. Hypercoagulation and hyperkinetic blood pressure indicative of physiological loss-of-control despite behavioural control in Africans: The SABPA study. Blood Press 2016; 25:219-27. [PMID: 26806201 DOI: 10.3109/08037051.2015.1131432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVES A dissociation between behavioural (in-control) and physiological parameters (indicating loss-of-control) is associated with cardiovascular risk in defensive coping (DefS) Africans. We evaluated relationships between DefS, sub-clinical atherosclerosis, low-grade inflammation and hypercoagulation in a bi-ethnic sex cohort. METHODS Black (Africans) and white Africans (Caucasians) (n = 375; aged 44.6 ± 9.7 years) were included. Ambulatory BP, vascular structure (left carotid cross-sectional wall area (L-CSWA) and plaque counts), and markers of coagulation and inflammation were quantified. Ethnicity/coping style interaction was revealed only in DefS participants. RESULTS A hypertensive state, less plaque, low-grade inflammation, and hypercoagulation were more prevalent in DefS Africans (27-84%) than DefS Caucasians (18-41%). Regression analyses demonstrated associations between L-CSWA and 24 hour systolic BP (R(2) = 0.38; β = 0.78; p < 0.05) in DefS African men but not in DefS African women or Caucasians. No associations between L-CSWA and coagulation markers were evident. CONCLUSION Novel findings revealed hypercoagulation, low-grade inflammation and hyperkinetic BP (physiological loss-of-control responses) in DefS African men. Coupled to a self-reported in-control DefS behavioural profile, this reflects dissociation between behaviour and physiology. It may explain changes in vascular structure, increasing cerebrovascular disease risk in a state of hyper-vigilant coping.
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Booysen V, Burger JR, du Plessis JM, Cockeran M. Assessment of post-operative pain medication adherence after day case orthopaedic surgery: A prospective, cross-sectional study. Int J Orthop Trauma Nurs 2019; 36:100718. [PMID: 31585861 DOI: 10.1016/j.ijotn.2019.100718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND AND AIM Patients struggle to adhere to prescribed pain medication after surgery because of, inter alia, side effects, sleep disturbances and pain severity. This study aimed to determine the influence of various factors on, the extent of adherence to prescribed post-operative pain medication (POPM) measured by participant-reported pill count (PRPC) following day case orthopaedic surgery at a private South African hospital. METHODS This prospective, quantitative cross-sectional study involving 120 participants (51 males, 69 females), used a structured questionnaire completed through a telephonic survey, 4 days after orthopaedic surgery. Measurements included PRPC adherence (adherent vs. non-adherent), in relation to post-operative adherence behaviour (POAB), normal medicine adherence behaviour (NMAB), pain severity affecting sleep and mobility, treatment side effects and patient demographic characteristics. RESULTS Based on PRPC measurement 56.7% (n = 68) of participants were adherent. PRPC was significantly associated with severe pain affecting falling sleep (p = .001), pain causing awakening from sleep (p = .035) and POAB (p < .001, Cramér's V = 0.5). PRPC adherence was independent from gender (p = .140), age (p = .822), smoking status (p = 1.000), type and event of side effects (p > .300), NMAB (p = .601) and the treatment regimen (i.e. unimodal vs. bimodal or multimodal) (p = .511). CONCLUSION Non-adherence (overuse or misuse) of prescribed POPM can be a result of severe pain, influencing sleep and movement after orthopaedic surgery, indicating a need for the review of these regimens in order to optimise care.
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Obeng-Kusi M, Lubbe MS, Cockeran M, Burger JR. Time-to-onset of treatment for hypertension and hyperlipidaemia in South African diabetes mellitus patients: A survival analysis using medicine claims data. J Clin Pharm Ther 2019; 44:701-707. [PMID: 31074041 DOI: 10.1111/jcpt.12844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/29/2019] [Accepted: 04/08/2019] [Indexed: 12/28/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Hypertension and hyperlipidaemia have high prevalence among diabetics and increase patients' risk of cardiovascular diseases, ultimately affecting prognosis negatively. Medicine claims data have gained prominence in the study of drug-related events and outcomes. There is paucity of publications on the time-to-onset of treatment for these conditions among South African diabetics using secondary data. This study aims to determine the time-to-onset of treatment for hypertension and hyperlipidaemia among diabetics using a South African medicine claims data. METHODS Survival analysis was conducted using retrospective data of patients enrolled continuously with a Pharmaceutical Benefit Management (PBM) company in South Africa from 1 January 2008 to 31 December 2016. We identified patients based on International Classification of Diseases, Tenth Revision (ICD-10) diagnoses codes for type 2 diabetes mellitus (E11) who were receiving antidiabetic medication according to the National Pharmaceutical Product Index (NAPPI) codes provided by the Monthly Index of Medical Specialities (MIMS) classification code 19.1 (N = 2996). Among these patients, we then selected those who had ICD-10 codes for hypertension (I10, I11, I12, I13, I15, O10 and O11) who were receiving antihypertensive medications, and those who had hyperlipidaemia (E78.5), who received antihyperlipidaemics during the study period. Data were extracted using SAS® system version 9.4 classification codes. The Kaplan-Meier approach, used to compare the survival experience of patients who commenced treatment for hypertension and hyperlipidaemia, was conducted using IBM® SPSS® version 25. The time to the commencement of treatment of hypertension and hyperlipidaemia among the diabetics were measured in days. With 2008 serving as the index year, we followed up on patients until 31 December 2016. RESULTS AND DISCUSSION A total of 494 patients with an average age of 53.5 (SD 11.1) years were included in the study, 34.8% of whom were females. Prevalence of hyperlipidaemia and hypertension among patients were 35.0% and 45.6%, respectively. Average time-to-onset of treatment for hyperlipidaemia was 2684.4 (SD 42.2) days compared to 2434.2 (SD 47.6) days for hypertension. There was no statistically significant difference in age and sex among patients who started treatment for either of these conditions during the study (P = 0.404; Cohen's d = 0.132 for hyperlipidaemia and P = 0.644, Cohen's d = 0.059 for hypertension). WHAT IS NEW AND CONCLUSION Within an average of 6 years after an index period of 1 year free of disease, diabetics may commence treatment for hyperlipidaemia, hypertension or both. With all significant data appropriately captured, medicine claims data can be effectively used in survival analysis to determine time-to-onset of treatment for hyperlipidaemia and hypertension among diabetics.
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Swanepoel AC, de Lange-Loots Z, Cockeran M, Pieters M. Lifestyle Influences Changes in Fibrin Clot Properties Over a 10-Year Period on a Population Level. Thromb Haemost 2021; 122:67-79. [PMID: 33906245 DOI: 10.1055/a-1492-6143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Case-control and observational studies have provided a plausible mechanistic link between clot structure and thrombosis. We aimed to identify lifestyle, demographic, biochemical, and genetic factors that influence changes in total fibrinogen concentration and clot properties over a 10-year period in 2,010 black South Africans. Clot properties were assessed with turbidimetry and included lag time, slope, maximum absorbance, and clot lysis time. Linear mixed models with restricted maximum likelihood were used to determine whether (1) outcome variables changed over the 10-year period; (2) demographic and lifestyle variables, biochemical variables, and fibrinogen single-nucleotide polymorphisms influenced the change in outcome variables over the 10-year period; and (3) there was an interaction between the exposures and time in predicting the outcomes. A procoagulant risk score was furthermore created, and multinomial logistic regression was used to determine the exposures that were associated with the different risk score categories. In this population setting, female gender, obesity, poor glycemic control, increased low-density lipoprotein cholesterol, and decreased high-density lipoprotein cholesterol contributed to the enhanced progression to prothrombotic clot properties with increasing age. Alcohol consumption on the other hand, offered a protective effect. The above evidence suggest that the appropriate lifestyle changes can improve fibrin clot properties on a population level, decreasing cardiovascular disease risk and thus alleviate the strain on the medical health care system.
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Joubert L, Burger JR, Truter I, Lubbe MS, Cockeran M. Methylphenidate and atomoxetine prescribing trends in children in the Western Cape Province of South Africa, 2005-2013. Health SA 2018; 23:1084. [PMID: 31934380 PMCID: PMC6917413 DOI: 10.4102/hsag.v23i0.1084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 03/20/2018] [Indexed: 11/16/2022] Open
Abstract
Background There is paucity of data on methylphenidate and atomoxetine prescribing patterns in South African children. Aim To describe the prescribing trends of these agents in children residing in the Western Cape Province. Setting South African private health sector. Methods Longitudinal drug utilisation study on medicine claims data from 2005–2013, focussing on the number of patients and prescriptions per patient. Results The total number of patients increased by 29.5% from 2005 to 2013. The majority were boys (male:female ratio, 3.5:1), and between the ages of > 6 and ≤12 years in 2005 and >12 and ≤18 years in 2013. More than 75% of patients received methylphenidate or atomoxetine in the City of Cape Town Metropolitan municipality. Prescriptions for methylphenidate and atomoxetine increased by 45.5% overall from 2005 to 2013 (p < 0.001), with that for methylphenidate and atomoxetine increasing by 36.0% and 314.5%, respectively. The average number of annual methylphenidate prescriptions per patient increased from 3.96 ± 2.92 (95% CI, 3.69–4.23) in 2005 to 4.38 ± 2.85 (95% CI, 4.14–4.61) in 2013 (Cohen’s d = 0.14) and for atomoxetine from 2.58 ± 1.86 (95% CI, 1.80–3.37) in 2005 to 4.85 ± 3.66 (95% CI, 3.84–5.86) in 2013 (Cohen’s d = 0.62). Conclusion Although the total number of patients and prescribing of methylphenidate and atomoxetine increased significantly from 2005 to 2013, a slight downward trend was observed in the mean number of prescriptions per patient per year from 2008 onwards. These prescribing patterns warrant further research.
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Meuwesen WP, du Plessis JM, Burger JR, Lubbe MS, Cockeran M. Investigation of the coexistence of CKD and non-communicable chronic diseases in a PBM company in South Africa. S Afr Fam Pract (2004) 2016. [DOI: 10.1080/20786190.2016.1151641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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