Method II

SUBJECTS AND METHODOLOGY

Study

:

Study population consisted of newly, diagnosed hypertensive patients with albuminuria using urinary albumin strips and was referred to as the subjects and those that were negative for albumin in their urine as the controls. They were matched for: age, sex, body mass index.

Hypertension was defined as systolic blood pressure of 140mmHg and above and or diastolic blood pressure of 90mmHg and above⁴. Patients were recruited into the study after they had given informed consent.

Location of the study:

This study was carried out in the medical wards, medical outpatient clinic, and the general out patient department of the University College Hospital (UCH), Ibadan, Oyo-State.

Data was collected using a standard questionnaire to obtain information on age, gender, and family history of hypertension. The blood pressure was measured using mercury column sphygmomanometer with appropriate cuff sizes after the patients had rested for a period of fifteen minutes. Korotkoff’s sounds I and V were taken as the systolic blood pressure (SBP) and diastolic blood pressure (DBP) respectively. Two Blood pressure readings were taken at intervals of two minutes and the average blood pressure calculated and recorded.

Study Design

The study design was an observational, cross sectional study with recruitment over twelve month’s period.

Inclusion criteria

2. Patients who have given informed consent Exclusion criteria

1. Patients with urinary tract infection or overwhelming sepsis 2. Patients with polycystic kidney disease, diabetes

3. Patients in congestive cardiac failure.

4. Patients who refuse to give consent 5. Patients on drug therapy.

Conduct of the study:

I.

A questionnaire designed to obtain demographic information and other information related to hypertension, diabetes and cigarette smoking was administered. History of polycystic kidney disease in the family was sought. Patients were physically examined for evidence of long standing hypertension, atherosclerosis, and irregular pulse rate. All subjects had their height measured in meters using an adjustable wall rule, with the subjects, standing with the back to the measuring rod, and looking straight ahead without (Both the subjects and the controls ) wearing shoes, caps or head – gear. Weight was measured to the nearest kilogram on a beam balance scale. The body mass index (BMI) was, subsequently calculated using the formula weight/height (kg/meter²). All measurements were made by the author.

II. Urine Analysis

The subjects and the controls were chosen from the newly diagnosed hypertensive patients referred to the University College Hospital Ibadan. The subjects have albuminuria on dip stick

For both subjects and controls, urine was tested for albumin with albustix using dip sticks method, and those that were positive were recruited as the subjects, and those that were negative were recruited as controls. The subjects were, further assessed using an over night urine collection over eight hours period. Patients were asked to empty their bladder at time zero and discard the urine, any other urine passed was collected into the provided container and at exactly eight hours after, the urine was passed into the container and returned to the hospital.

Standard was produced from the parent stock of 1ml of 30% bovine albumin into various dilutions (using the formula RV/O where R is the required concentration, V is the final volume and O is the original concentration) and a standard curve was generated. Two millilitres of bromocresol green was added to 20µl of the urine sample. The absorbance was read at 628nm using a spectrophotometer, and the results were plotted to the already generated standard curve and urinary albumin concentrations were then determined. For the urinary creatinine, 4.95mls of distill water was added to 0.05mls of urine sample, 3mls of the solution was added to 1ml of picric acid of 0.04 molar and 1ml of 0.75 molar of sodium hydroxide. After twenty minutes, the absorbance was read at 540nm with a spectrophotometer. The actual creatinine concentration in the urine was calculated using this formula:

Optical density of urine sample × Conc of standard Optical density of the standards

The result obtained was then used to calculate the albumin- creatinine ratio in each sample.

The glomerular filtration rate was determined using the Cockroft and Gault formula.

Cockroft and Gault formula:-

(140 – age) x weight (kg) x (0.85 for women)

III: Renal Ultrasound

The ultrasound machine used was Aloka, SSD – 1700, dynaview – II, the probe used was Aloka with frequency of 3.5MHz and the gel used was ultrasound gel

The ultrasonography examination of the kidneys was carried out with the patients in supine position; sonographic gel was applied to aid the scanning. A 3.5MHz probe frequency was used for the renal ultrasound. The supine position is good for the right kidney using the liver as the ultrasound window while the prone and oblique positions give better view for measurement of the left kidney parameters. The kidney length was measured by a line joining the two poles of the kidney, sometimes the measurements were repeated. The measurements were done by two sonologists and the investigator in attendance.

The grading of echogenicity is kidney < spleen < liver < pancreas. The degree of kidney parenchymal echogenicity is graded as follows⁵³.

Grade I: The renal parenchymal echogenicity equals that of the liver

Grade II: The renal parenchymal echogenicity is greater than that of the liver.

Grade III: The echogenicity of the renal parenchymal is equal to the renal sinus echoes.

Data Analysis:

The data generated was entered into the case record form and later transferred into the computer. The discrete variables were summarized as means while the categorical variables were expressed as proportions. The frequencies of findings by physical examinations, laboratory tests and renal ultrasounds were determined. The subjects were divided on the bases of the severity of hypertension, the BMI, the GFR and the renal ultrasound findings. Analysis of data was done using a statistical software package SPSS version 11. Categorical variables

comparison such as sex, comparison with respect to renal ultrasound findings were done using chi – square test. Multiple regression analysis was also applied. Statistical significance was taken as p<0.05

CHAPTER FIVE