Clinical Significance of Elevated Levels of Cardiac Troponin T in Patients with Chronic Kidney Disease at Lagos University Teaching Hospital, Lagos.

BACKGROUND: This is an observational study of pre-dialysis patients with Chronic Kidney Disease (CKD) attending nephrology clinic at Lagos University Teaching Hospital to determine the clinical significance of elevated levels of Cardiac Troponin T (CTT) and possible associated factors. METHODS: One hundred and forty-three (143) patients with CKD and no prior history of myocardial infarction were recruited and their serum levels of CTT were determined within 3 months of sample collection and storage at -80° C. ECG findings and clinical variables were compared. The 99 percentile cut-off value was derived using healthy individuals that met the inclusion criteria. RESULTS: Mean blood CTT level was significantly higher in CKD patients compared to the general population. The 99th percentile value derived in the reference sample population was 48.02pg/ml. Statistical analysis showed significant association of CTT elevation with left ventricular hypertrophy, decreased renal function and age. CONCLUSION: CTT is generally elevated in pre-dialysis patients with CKD and a single elevated blood level of CTT above the 99th percentile may suggest asymptomatic Acute Coronary Syndrome. Serial rising levels of CTT and other clinical features will be of diagnostic significance in the diagnosis and management of asymptomatic acute coronary syndrome in patients with CKD.

CONTEXTE: Étude observationnelle de patients prédialysés atteints d'une maladie rénale chronique (MRC) fréquentant une clinique de néphrologie de l'hôpital universitaire de Lagos afin de déterminer la signification clinique des niveaux élevés de troponine cardiaque T (TTC) et des facteurs associés possibles. METHODESS: Cent quarante-trois (143) patients atteints de MRC et aucun antécédent d'infarctus du myocarde ont été recrutés et leurs taux sériques de TTC ont été déterminés dans les 3 mois suivant le prélèvement et le stockage de l'échantillon à -80 °C. Les résultats de l'ECG et les variables cliniques ont été comparés. La valeur seuil du 99e centile a été calculée à partir de personnes en bonne santé qui répondaient aux critères d'inclusion. RESULTATSS: Le taux moyen de TTC dans le sang était significativement plus élevé chez les patients atteints de MRC que dans la population générale. La valeur du 99e centile calculée dans la population de l'échantillon de référence était de 48,02pg/ml. L'analyse statistique a montré l'association significative de l'altitude de TTC avec l'hypertrophie ventriculaire gauche, la fonction rénale diminuée et l'âge. CONCLUSION: Le CTT est généralement élevé dans les patients de pré-dialyse atteints de MRC et un taux sanguin élevé simple de CTT au-dessus du 99ème centile peut suggérer ACS qui n'a pas été remarqué. Les niveaux ascendants périodiques de CTT et d'autres dispositifs cliniques seront d'importance diagnostique dans le diagnostic et la gestion de ces patients atteints de MRC mais asymptomatique pour le syndrome coronaire aigu. MOTS-CLÉS: Troponine cardiaque T, Syndrome coronarien aigu, Maladie rénale chronique, hypertrophie ventriculaire gauche.

Calcium and Magnesium Metabolism in Pre-Eclampsia.

BACKGROUND: Preeclampsia is a multisystem disorder associated with high maternal and perinatal mortality and morbidity. The cause of the disorder is largely unknown and its pathogenesis is complex and poorly understood. Calcium and magnesium are divalent ions which may have roles to play in the manifestations of the disease. An understanding of their metabolism in preeclampsia may aid our management of pregnant women who develop the disease. OBJECTIVE: To determine the plasma and urinary concentrations of calcium, magnesium and parathyroid hormone in women with mild, severe preeclampsia and in normal pregnancy. METHODS: This is was a case control study of fifty women with mild preeclampsia, fifty women with severe preeclampsia and fifty women with normal pregnancy as controls, drawn from The Antenatal Clinic at the Lagos University Teaching Hospital, Lagos, Nigeria. The women were consecutively recruited after signing an informed consent form. Ethical approval was obtained from the medical ethics committee of the hospital. RESULTS: The three groups of women were similar in their socio demographic characteristics. Plasma calcium was low in mild and severe preeclampsia compared to normal pregnancy controls (p=0.021). Urine calcium/creatinine ratio was lower in mild and severe preeclampsia compared to normal pregnancy controls (p= 0.030). Fractional excretion of calcium and levels of parathyroid hormone were similar across all three subgroups of women. Plasma magnesium was higher in mild and severe preeclampsia compared to normal pregnancy controls (p=0.011) and showed a positive correlation with plasma creatinine (r=0.48, p=0.045). Parathyroid hormone levels were similar across the study groups. CONCLUSION: Preeclampsia is associated with significant changes in calcium and magnesium metabolism. This study noted significant hypocalcaemia in mild and severe preeclampsia with significantly low urine calcium/creatinine levels. Calcium supplementation may have a place in patient's management. Hypermagnesemia was observed in mild and severe preeclampsia and appeared related to renal function.

The prevalence of metabolic syndrome in persons with type 2 diabetes at the Lagos University Tteaching Hospital, Lagos, Nigeria.

BACKGROUND: Over the past decade, Lagos state has witnessed greater industrialization and increased economic prosperity. Lifestyle has become increasingly westernized, characterised by intake of excesscalories and physical inactivity. It is possible that these changes would lead to increases in the prevalence of metabolic syndrome and type 2 diabetes which are known cardiovascular risk factors. It became important therefore to study the prevalence of metabolic syndrome in type 2 diabetes in Lagos, Nigeria as at the present time and compare it with previous prevalence rates as well as rates from other centres as a way of assessing current cardiovascular risk burden in this population. OBJECTIVES: This study is to determine the prevalence of metabolic syndrome in type 2 diabetes and to correlate the presence of microalbuminuria with glycaemic control. METHODS: One hundred subjects with type 2 diabetes were selected by simple random sampling from patients attending The Diabetic Clinic at the Lagos University Teaching Hospital, Lagos, Nigeria.Age and sex matched controls were recruited from members of staff of the hospital.Clinical data was obtained by interviewing the participants. Anthropometric measurements were made and blood and urine specimens were collected for analysis. The World Health Organisation (WHO) criteria which is specified for the diagnosis of metabolic syndrome in the setting of type 2 diabetes was used to determine the prevalence of metabolic syndrome in this population. RESULTS: Central obesity had the highest prevalence (79%) among persons with diabetes,followed by hypertension (69%), low HDL (50%), general obesity (40%), microalbuminuria (24%) and hypertriglyceridemia (10%). The prevalence of metabolic syndrome was 86%in this group. The commonest occurring metabolic syndrome component among patients with type 2 diabetes and metabolic syndrome was obesity (91.9%). There was a moderate positive correlation(r=0.52; p=0.01) between HbA1c values and microalbuminuria in persons with diabetes and the metabolic syndrome. CONCLUSION: The prevalence of metabolic syndrome is very high among patients with type 2 diabetes in The Lagos University Teaching Hospital, Lagos, Nigeria.

The relationship between microalbuminuria, cardiovascular risk factors and disease management in type 2 diabetes.

BACKGROUND: In patients with type 2 diabetes, microalbuminuria is an early clinical sign suggestive of vascular damage to the glomerulus. Microalbuminuria has also been currently reported as an important risk factor for cardiovascular disease and becomes relevant in the management of type 2 diabetes. OBJECTIVES: This study is to determine the prevalence of microalbuminuria, identify the risk factors associated with microalbuminuria in type 2 diabetes, and to asses the achievement of treatment goals for cardiovascular risk reduction in type 2 diabetics. SUBJECTS AND METHODS: Seventy- two subjects with microalbuminuria were recruited from three hundred consecutively screened type 2 diabetics attending the Diabetic Clinic at the Lagos University Teaching Hospital. Clinical data were obtained by interviewing the participants. Anthropometric measurements were made and blood specimens were collected for analysis. RESULTS: The prevalence of microalbuminuria was twenty-four percent (24%) in type 2 diabetes. Multiple logistic regression identified duration of diabetes (odds ratio 1.3 (95% CI; 0.03-1.58), hypertension(odds ratio 5.2 (95% Cl; 1.24-18.62), Body mass index (BMI) (odds ratio 1.27 (95% CI; 1.0-1.6), waist/hip ratio (WHR) (odds ratio 1.9 (95% Cl; 1.3-3.5), andHbA,c (odds ratio 6.6 (95% Cl; 1.02-27) as independent risk factors associated with microalbuminuria in type 2 diabetics. Optimum blood pressure, glycemic and weight control were achieved in eighty five percent (85%), fifty eight percent (58%) and nineteen percent (19%) of the type 2 diabetes respectively. CONCLUSION: This study showed that microalbuminuria is common among patients with type 2 diabetes. It also showed improvement in glycemic control and modifiable cardiovascular risk factor control when compared with previous studies.

Salt-sensitivity in normotensive and hypertensive Nigerians.

BACKGROUND: Salt-sensitivity increases the risk for the development of high blood pressure in susceptible persons and also increases the risk for cardiovascular events and mortality. OBJECTIVE: The study is to determine the pattern of salt-sensitivity among normotensive and hypertensive Nigerians. METHODS: Twenty-eight (28) hypertensive subjects (HT) and twenty-five (25) age-matched normotensive controls (NT) were given 200 mmol/day salt as sodium chloride for 5 days after control parameters had been determined. Subjects were regarded as salt-sensitive when change in mean arterial blood pressure (cMABP) between baseline levels and that after salt loading was > or = 5 mmHg. RESULTS: Systolic blood pressure and mean arterial blood pressure but not diastolic blood pressure rose significantly (p < 0.05 and p < 0.001 respectively) in NT subjects while all the parameters showed significant increases in hypertensive subjects (SBP p < 0.01; DBP p < 0.001; MABP p < 0.0001). More hypertensive subjects (60.7%) were salt-sensitive compared with normotensive (52.0%) subjects (p < 0.05). CONCLUSION: This study has demonstrated pressor responses to acute salt-loading in normotensive and hypertensive Nigerians and salt-sensitivity was higher in hypertensive subjects.

Relationship between salt intake, salt-taste threshold and blood pressure in Nigerians.

BACKGROUND: Many studies have found an association between sodium intake and blood pressure. Salt taste threshold is thought to be another marker of sodium intake. OBJECTIVE: This study sought to assess two markers of sodium intake, 24-hour-urinary sodium and salt-taste threshold. We also determined the relationship between these two markers and blood pressure. METHODS: Salt taste threshold was measured by the ability of the subjects to discern the taste of salt in graded solutions of saline. Twenty-four urinary sodium was measured by flame photometry in a 24-hour urine collection. Other plasma and urine electrolytes and creatinine were measured using standard automated chemistry methods. RESULTS: There was a significantly higher salt intake measured as 24-hour urinary sodium/mmol of creatinine in the hypertensive group, (36.6±20mmol/L/mmol creatinine) compared with the normotensive group (14.8±5.8mmol/L/mmol creatinine) p<0.001. Urinary potassium was also higher in the hypertensive subjects. When the subjects were grouped into low and high salt taste threshold, the high salt threshold group also had significantly higher 24 hour urinary sodium (30.3±5mmol/L creatinine vs the low STT urinary sodium of (19.5±14 p <.05). CONCLUSION: Sodium intake measured as 24-hour urinary sodium is increased in subjects with hypertension attesting to sodium intake as a risk factor for the development of high blood pressure. Subjects with high salt taste threshold also have increased urinary sodium excretion which may predispose them to development of hypertension.

Osteocalcin and specific markers of bone resorption in sickle cell disease.

Sickle cell disease commonly causes avascular necrosis of bone. Plain radiographs are not useful if obtained early in the disease. Radionuclide scans do not appear to increase the sensitivity of the diagnosis. Magnetic resonance imaging can detect disease but this is expensive and hard to employ on a routine or regular basis. The determination of the following new biochemical markers of bone metabolism has not been previously performed in sickle cell disease: serum osteocalcin (S-BGP), urinary cross-linked aminoterminal telopeptide of type I collagen (INTP or NTx) and urinary deoxypyridinoline (U∼DPD). As a first step or preliminary study we evaluate the usefulness of these biochemical markers of bone metabolism, by measuring the plasma or serum and urine levels of these markers in 20 adult patients with sickle cell disease. There was no change in S-BGP (p<0.9) a biochemical marker of bone formation. The two markers of bone resorption, urinary NTx (p<0.002) and U-DPD (p<0.001) increased highly significantly. Although the mean values of urinary NTx and U-DPD were significantly elevated in five patients with clinical evidence of bone complications, only two of these subjects had values above mean +2 SD of normal (control) mean values. Hence the sensitivity and specificity of these measures need to be further investigated with a larger sample size. There was significant correlation (P < 0.001) between NTx and U-DPD. These preliminary findings indicate that urinary NTx and U-DPD should be further investigated as possible biochemical markers of skeletal changes in SCD.

Biochemical markers, extracellular components in liver fibrosis and cirrhosis.

Liver fibrosis and cirrhosis are common sequelae to diverse liver injuries in the tropics or Nigeria. The development of hepatic fibrosis or cirrhosis is due to increased synthesis, deposition, and possibly reduced degradation of hepatic extracellular matrix components, especially collagens, such as interstitial type I and III, basement membrane type IV, microfibrillar type VI, and pericellular type V, non-collagenous proteins, such as laminin, fibronectin, undulin, etc., and various types of proteoglycans, such as hyaluronan, etc. In Nigeria, the common approach for diagnosing or assessing the activity of connective tissue in this organ is the histological examination of a biopsy, if one is performed by a specialist physician. The liver biopsy provides a static picture of the changes that have already taken place in the liver. Another possible method is (where the facilities are available) a quantitative assessment of the liver biopsy by biochemical determination of total collagen via hydroxyproline. Biopsy is an invasive method and cannot be repeated often enough in the bid to ensuring an intensive follow-up of the changes taking place during the course of antifibrotic treatment or therapy. Thus, serum or other biological fluid assays for connective tissue proteins, such as the aminoterminal propeptide of type III Procollagen PIIINP, or the dimeric carboxyterminal domain of type IV collagen known as NCl or PIVCP, laminin, and others are essentially non-invasive and can be carried out repeatedly. In addition, the measurement of certain enzymes of connective tissue proteins in serum may the reflect activity of liver fibrogenesis. They offer the potential for diagnosis and therapeutic control. However, it is very important to note that circulating biochemical markers of fibrogenesis, fibrolysis or both may not reflect hepatic fibrosis or cirrhosis, since they are not liver-specific. Thus, the best diagnostic approach would be the identification and measurement in serum of the driving force of fibrogenic process.

Osteocalcin and bone-specific alkaline phosphatase in sickle cell haemoglobinopathies.

Osteocalcin or bone gamma-carboxyglutamic acid (gla) protein and Bone-specific alkaline phosphatase (b-AP) total protein levels were evaluated as indicators of bone turnover in twenty patients with sickle cell haemoglobinopathies and in twenty normal healthy individuals. The serum bone-specific alkaline phosphatase total protein level was measured by immunoradiometric (IRMA) method. The concentrations of serum bone-specific alkaline phosphatase total protein were higher in the study group than in the control group [P < 0.05]. The serum osteocalcin (BGP) showed no significant difference with the control healthy subjects. There was no correlation between the serum osteocalcin and serum bone-specific alkaline phosphatase total protein in the patient group. In conclusion, serum bone-specific alkaline phosphatase total protein determined or measured by IRMA can be considered a sensitive marker of bone turnover and could be especially useful as valuable non-invasive biochemical marker for identifying sickle cell patients with bone complications.

Body proportions in three Nigerian tribes.

Prediction equations of body composition based on measurements of whole-body bioelectrical impedance analysis (BIA) have been found to be population-specific. It was hypothesised that this may be, in part, due to differences in proportional limb lengths between ethnic or racial groups. As a preliminary to a survey of body composition in urban Nigerians using BIA, the relative limb lengths of the three major tribal groups (Hausa, Yoruba and Ibo) were determined. We found small (5-9%) but significantly longer limb lengths in Nigerians compared to a Caucasian population, but no significant differences between tribes. This implies that BIA prediction equations generated in a Caucasian population are inappropriate for use in a Nigerian population.