Title: Presenting Data Using Graphs and Summary Statistics and Quantifying Uncertainty in Study Findings |
Dyslipidaemia Study in Diabetes: Study description
A cross sectional study was conducted on 366 diabetic patients to assess the lipid profile and to investigate possible factors contributing to the development of dyslipidemia as well as hemoglobin A1c (a measure of sugar control for diabetic patients). The patients were recruited from a specialized diabetic hospital outpatient department. All study participants provided a blood sample and completed a lifestyle and demographic questionnaire.
The objective of the study was to find factor(s) that may relate to the risk of developing dyslipidemia in diabetic patients. Along with the demographic information and physical measurements, hematological measurements were reported in continuous scale. For analysis purposes most of the continuous variables were transformed into grouped data. However, original continuous variables were also kept in the data set. The short and long names of the variables and corresponding statistical codes are presented in the following table, Table 1.
Table 1: Variable description of the Dyslipidaemia study
Variable | Variable Label | Value label |
ID | ID Number | N/A |
Age | Age in years | N/A |
Age_gr | Age group | 1: < 40 years; 2: 40 – 49 years; 3: 50 – 59
years and 4: >= 60 years |
Gender | Gender | 1: Male , 2: Female |
Occupation | Occupation type | 1: Sedentary worker; 2: Moderate worker
and 3: Heavy physical worker |
Physical_activity | Physical activity level | 0: Sufficient PA and 1: Insufficient PA |
Weight | Weight in Kg | N/A |
Height | Height in meter | N/A |
BMI | BMI in Kg/m2 | N/A |
BMI_gr | BMI Group | 0: Normal; 1: Overweight and
2: Obese |
BP_diastolic | Diastolic BP | N/A |
BP_systolic | Systolic BP | N/A |
HTN | Hypertension | 0: Normotensive and 1: Hypertensive |
Duration_diabetes | Duration of Diabetes | N/A |
Duration_diabetes_gr | Duration of Diabetes Group | 1: < 5 years; 2: 5 – < 10 years and
3: > = 10 years |
HbA1c | HbA1c | N/A |
HbA1c_gr | HbA1c group | 0: <7 Controlled and 1: >=7 Uncontrolled |
Insulin | Takes insulin | 0: No and 1: Yes |
Duration_insulin | Duration of insulin (years) | N/A |
TC | Total Cholesterol | N/A |
TC_gr | Total Cholesterol group | 0: < 200 and 1: ≥ 200 |
TG | Triglyceride | N/A |
TG_gr | Triglyceride group | 0: < 150 and 1: ≥ 150 |
HDL | HDL Cholesterol | N/A |
HDL_gr | HDL Cholesterol group | 0: Normal and 1: Low |
LDL | LDL Cholesterol | N/A |
LDL_gr | LDL Cholesterol group | 0: < 100 and 1: ≥ 100 |
Creatinine | Serum Creatinine | N/A |
Creatinine_gr | Serum Creatinine | 0: < 1.5 and 1: ≥ 1.5 |
TC_HDL | TC_HDL ratio | N/A |
LDL_HDL | LDL_HDL ratio | N/A |
Dyslipidaemia | Dyslipidaemia | 0: No dyslipidaemia and 1: Yes
dyslipidaemia |
Questions 1-4 are related to the “Dyslipidemia Data”.
Question 1 Identify each of the first 15 variables (marked bold) in the above table either as nominal, ordinal, discrete or continuous.
Hint: Present your answer in a table by listing the variables in the first column, variable label in the 2nd column, value label in the 3rd column and classification of the variables in the 4th column.
Variable | Variable Label | Value label | Classification of Variable |
ID | ID Number | N/A | N/A |
Age | Age in years | N/A | Continuous |
Age_gr | Age group | 1: < 40 years; 2: 40 – 49 years; 3: 50 – 59
years and 4: >= 60 years |
Ordinal |
Gender | Gender | 1: Male, 2: Female | Nominal |
Occupation | Occupation type | 1: Sedentary worker; 2: Moderate worker
and 3: Heavy physical worker |
Ordinal |
Physical_activity | Physical activity level | 0: Sufficient PA and 1: Insufficient PA | Nominal |
Weight | Weight in Kg | N/A | Continuous |
Height | Height in meter | N/A | Continuous |
BMI | BMI in Kg/m2 | N/A | Continuous |
BMI_gr | BMI Group | 0: Normal; 1: Overweight and
2: Obese |
Ordinal |
BP_diastolic | Diastolic BP | N/A | Continuous |
BP_systolic | Systolic BP | N/A | Continuous |
HTN | Hypertension | 0: Normotensive and 1: Hypertensive | Nominal |
Duration_diabetes | Duration of Diabetes | N/A | Continuous |
Duration_diabetes_gr | Duration of Diabetes Group | 1: < 5 years; 2: 5 – < 10 years and
3: > = 10 years |
Ordinal |
HbA1c | HbA1c | N/A | Continuous |
Question 2 : Fill up the following table using appropriate summary statistics for each of the variables listed in the first column. Discuss whether dyslipidaemia is related to HbA1c, diastolic BP, physical activity level and patients’ age group. Note: outcome variable is dyslipidaemia
Variable | Dyslipidaemia | |
Yes | No | |
HbA1c | Median 80 IQR 15 | Median 80 IQR 13 |
BP diastolic | Mean 81.84 SD 11.100 | Mean 77.02 SD 10.601 |
Physical Activity level: | ||
Sufficient | 45.3% | 54.4% |
Insufficient | 54.7% | 45.6% |
Age group: | ||
< 40 yrs. | 81% | 19% |
40 – 49 yrs. | 87.4% | 12.6% |
50 – 59 yrs. | 82.2% | 17.8% |
≥ 60 yrs. | 89.7% | 10.3% |
Question 3 : Graphically determine the relationship between dyslipidaemia and each of the following variables: duration of diabetes group, BMI group and occupation type. Present each of the above variables on an appropriate graph and discuss the results followed by a conclusion. Note: outcome variable is dyslipidaemia
Question 4 : Graphically determine the relationship between HbA1c and each of the following variables: occupation type, duration of diabetes group and BMI group. Present each of the above variables on an appropriate graph and discuss the results followed by a conclusion. Note: outcome variable is HbA1c
Question 5 : For the following questions show the detailed calculations, most marks will be allocated for correct calculations.
- [4 marks] The lifetime of a mechanical aortic valve is normally distributed with a mean life of 30 years and a standard deviation of 2 years. Find the chances that a randomly selected patient who had an aortic valve replacement will not be required to replace his/her valve in the next 32 years.
- [6 marks] At a hospital, the ages of all new employees hired during the last 5 years are normally distributed. Within this curve, 95% of the ages, centered about the mean, are between 6 and
37.4 years. Find the mean age and the standard deviation of the data.
- [6 marks] Given that the scores on a medical test follow a normal distribution with a mean of 460 and a standard deviation of 100. If all students in a class of 41 attend the test what is the probability that the given class will obtain a mean score of above 590?
Question 6 : Consider that the population distribution for length of survival time after diagnosis with a lung cancer is right skewed. What will be the shape of the sampling distribution for the sample mean length of survival in a random sample of 2500 lung cancer patients from this population? Justify your answer. Hint: only statement of the “Central Limit Theorem” would not be considered as a complete answer.
Question 7 : State the learning outcomes of Modules 1-3 and describe how this assessment is aligned with these learning outcomes (maximum of 150 words, excluded from the total word count of this assessment).