2. Case 1
Suppose a physician failed to act on a lung lesion detected in patient's pre-operative (for hernia surgery) chest x-ray.
There was no CT scan follow-up, and it wasn't until a year later that the patient was diagnosed with lung cancer. What
statistical perspective can be given regarding the impact of the year's delay on the man's prognosis? Use the findings of
publication:
Supplementary questions:
Would You rather use survival or cure rates?
What other initial points to study survival would You suggest?
3. Case 2
*Abstract. The study aims to analyze in detail the incidence, mortality using the standardized incidence ratio (SIR), and
standardized mortality ratio (SMR) of hepatocellular carcinoma (HCC) in primary biliary cirrhosis (PBC), because no large
case studies have focused on the detailed statistical analysis of them in Asia. Methods. The study cohorts were
consecutively diagnosed at Gunma University and its affiliated hospitals. Age- or sex-specific annual cancer incidence and
deaths were obtained from Japanese Cancer Registry and Death Registry as a reference for the comparison of SIR or SMR
of HCC. Moreover, univariate analyses and multivariate analyses were performed to clarify predictive factors for the
incidence of HCC. Results. The overall 179 patients were followed up for a median of 97 months. HCC had developed in
13 cases. SIR for HCC was 11.6 (95% confidence interval (CI), 6.2–19.8) and SMR for HCC was 11.2 (95% CI, 5.4–20.6) in
overall patients. The serum albumin levels were a predictive factor for the incidence of HCC in overall patients.
Conclusions. The incidence and mortality of HCC in PBC patients were significantly higher than those in Japanese general
population. PBC patients with low serum albumin levels were populations at high risk for HCC.
Tasks
1. Give formulae of:
sex-specific annual cancer incidence and
mortality of HCC
SIR and SMR of HCC
2. Draw conclusions based upon findings
(table to the right)
3. What univariate analyses and
multivariate analyses You suggest to
clarify predictive factors for the incidence
of HCC
*Kenichi Hosonuma, Ken Sato. Incidence, Mortality, and Predictive Factors of Hepatocellular Carcinoma in Primary Biliary Cirrhosis. Gastroenterology Research and
Practice Volume 2013 |Article ID 168012 https://www.hindawi.com/journals/grp/
4. Case 3
The crude mortality rate for all ages in the United States for 1995-1997 is 8.7 per 1,000 population. In Mexico it is much
lower: 4.7 per 1,000 population. We can conjecture that the higher rate in the United States may be due to an older
population structure than in Mexico. Therefore, we wish to study the rates of the two countries when controlling for the
effect of the age structure difference. Giving data below draw comparison by calculating age-standardized mortality rates
in Mexico and the United States, using the direct method*
Supplementary questions:
What are the other factors to be adjusted for to draw less biased comparison?
What other standardization technics You see appropriate given the case.
*Source of the data: Pan American Health Organization. Perfiles de mortalidad de las comunidades hermanas fronterizas México - Estados Unidos Edición 2000 / Mortality
profiles of the Sister Communities on the United States-Mexico border 2000 Edition. Washington, D.C.: OPS. 2000
5. Case 4
The crude mortality rate in Colombia in 1999 was 4.4 per 1,000 population, with variations between 1.8 per 1,000
population in the state of Vichada and 6.9 per 1,000 in Quindio.1 We would like to study the possible significant
differences in the observed mortality in the country and in its states. The case of the state of Vichada is presented in this
case. Use indirect standardization to compare mortality in the Colombian department of Vichada and mortality in
Colombia in general
Table below contains information (by columns)
- Age groups brackets (A)
- The age-specific mortality rates by age group in Colombia (B)
- The population of the state of Vichada stratified by age (C)
- The total number of deaths observed in the department of Vichada (D) *
A B C D
Supplementary questions:
What are the other factors to be adjusted for to draw less biased comparison?
What other standardization technics You see appropriate given the case.
*Source of the data: Situación de Salud en Colombia. Indicadores Básicos 2002. 2002 [Folleto producido por el Ministerio de Salud de Colombia y la Representación
OPS/OMS en Colombia]
6. Case 5
In this case we use the data of a historical follow-up study among foundry workers. In this study, the employees of 37
foundries were traced back to the 1950's (approximately 17,700 persons). The vital status could also be traced
sufficiently completely over the decades by means of the population registers (loss to follow-up of 6.2%). However the
death certificates could only be obtained for about 70% of all deaths, Table 1 shows selected SMRs based on these data
(Adzersen et al. 1997*). Table below contains information on observed (O) and expected (E) deaths #.
Questions:
What are the formulae for SMR, CL (95% confidence limits)?
What method of standardization is most appropriate to the case?
What are the possible deductions?
What are the possible corrections to the bias caused by loss to follow-up?
*Adzersen K.H., Becker N., Steindorf K., and Frentzel-Beyme R. (1997), Cancer Mortality in a Germen Cohort of Male Iron Foundiy Workers, Heidelberg: German
Cancer Research Center.
7. Case 6
Introduction: The carcinogenic potency of chrysotile-asbestos remains a contentious topic. We examine cause-specific
mortality, especially lung cancer, and its association with chrysotile-asbestos exposure in a Chinese cohort. Methods: A
cohort of 577 workers from a chrysotile-textile plant was followed prospectively from 1972 to 2008. Occupational
history, exposure information, and smoking data were obtained from company records and personal interviews. Excerpt
of results is given in table below*
Questions:
What are the formulae for SMR, CL (95% confidence limits)?
What method of standardization is most appropriate to the case?
What are the possible deductions?
What are the possible corrections to the confounding of birth period with age at entry?
*Sihao Lin, PhD,* Xiaorong Wang, PhD, et.al. Cause-Specific Mortality in Relation to Chrysotile-Asbestos Exposure in a Chinese Cohort.//Journal of Thoracic Oncology •
Volume 7, Number 7, July 2012 p.1109-1114
8. Case 7
Please explain situation given in graphs below. Why the same counties of US feature both highest and lowest SMR due
to kidney cancer?
Supplementary questions:
What are the formulae for SMR, its CL
(95% confidence limits)?
What method of standardization is most
appropriate to the case?
What are the possible corrections?
*Sihao Lin, PhD,* Xiaorong Wang, PhD, et.al. Cause-Specific Mortality in Relation to Chrysotile-Asbestos Exposure in a Chinese Cohort.//Journal of Thoracic Oncology •
Volume 7, Number 7, July 2012 p.1109-1114
9. Case 8
Demographic analysis permits highlighting a vicious and a virtuous circle of education quality according to whether
fertility is high or low. In the table below both circles start at 2000 followed by coming generations events.
Questions:
What demographic indices they use to
describe both models?
Give formulae of mentioned indices.
Do You agree that high fertility provokes
vicious circle that maintains low quality
education?
Is it the same with commonwealth?
10. Case 9
Given evolutions of the fertility rate and life expectancy in Malaysia (Figure 1-2) explain possible drivers of diminishing
dependency ratio both nationwide and across states (Figure 3).
Supplementary questions:
Give formulae of indices displayed.
Do You agree that drop in fertility
safeguards decrease in dependency
ratio?
Do such tidings ensure sustainable
commonwealth?
What dynamic of quality of health
services is anticipated? Explain why.
11. Case 10
Given excerpt of Nigeria case* data discuss current perception of demographic situation (second column of table below).
Supplementary questions:
Give formulae of indices displayed.
Do You agree that increase in
dependency ratio is anticipated?
Does such perception facilitate
sustainable commonwealth? Explain
why.
*Case studies in population policy: Nigeria (Population policy paper №16 ). UN, NY, 1988.
