MODELLING SURVIVAL DATA OF THALASSAEMIA PATIENTS IN PAKISTAN

Authors

  • Jamal Abdul Nasir
  • Syed Arif Ahmed Zaidi

Abstract

Background: Fatimid Foundation with its centers serves as a charitable organization for millionsof blood disease carriers in Pakistan. This retrospective survival study is an analysis of theThalassaemia patients registered in Multan centre who are followed up to nine years to assess thegender risk of death. Methods: Data on 120 patients of Thalassaemia during 1994-2002 wasanalyzed. The standard Kaplan-Meier and Nelson-Aalen procedures were used to compare thesurvival function of the male and female patients of Thalassaemia. The statistical significance wasalso assessed using log rank test. The Cox Proportional Hazards (PH) model using a forwardselection procedure was used to identify the potential factors associated with the increase risk ofdeath. Results: By ignoring the censoring, the average survival time of males and females werecalculated to be 1308.1 and 1574.7 days respectively. The average hazard rate for the femalegroup was 0.00033 and for the male group it was 0.00061. The median survival time wasestimated from the Kaplan-Meier survival curves (Males: 1400 days, Females: 1785 days). Underthe censoring mechanism, the mean survival time for males was calculated to be 1465.82 dayswith standard error of 146 days, where as for females it was calculated to be 1855.26 withstandard error of 151.82 days. When considering death as event of interest Under the Coxmodelling approach, we found a male patient of Thalassaemia was 1.484 times more likely to diewhen compared to his female counterpart. When considering the iron over load as the event ofinterest, we found a male patient of Thalassaemia was 1.753 fold more likely to reach excessiveHaemochromatosis level compared to female patient. Conclusion: The analysis reinforces thatfemale group prognosis is better than the male group. Further, our analysis of real survival data setshows that the high status of Haemochromatosis level is associated with the increased risk of deathin patients with Thalassaemia with other possible confounders.Keywords: Censoring; Cox PH model, Kaplan-Meier estimator, Nelson-Aalen estimator, Thalassaemia

References

Amin ST. Over 0.1 m suffer from Thalassaemia. The Dawn

(REVIEW) Nov 16, 2001 (13:23:37 +05:00) [Health-List]

Haider M. (07/11/2003). Enhanced Yearly Grant in Aid of Rs

,000 Million from 2004–05 for prevention program of

Thalassaemia Disease.

Kardauan O. Statistical Analysis of Male Larynx-Cancer

Patients: A case Study. Statistica Nederlandica 1983;37:103–26.

Sedmak DD, Meineke TA, Knechtges DS, Anderson J.

Prognostic Significance of Cytokeratin-Positive Breast

Cancer Metastases. Modern Pathology 1989;2:519–20.

Mitchell HG. Evaluating serial cancer marker studies in

patients at risk of recurrent disease. Biometrics 1981;37:67–78.

Franks P, Clancy CM, Gold MR. Health insurance and

mortality. JAMA 1993;270:737–41.

Saunders B, Baily S, Phillips M, Allsop S. Women with

alcohol problems: Do they relapse for reasons different to

their male counterparts? Addiction 1993;88:1413–22.

Lagakos SW, William JS. Models for censored survival

analysis: a cone class of variable-sum models. Biometrika

;65:181–9.

Kaplan EL, Meier P. Nonparametric estimation from

incomplete observations. Journal of American Statistical

Association 1958;53:457–81.

Cox DR, Oakes D. Analysis of Survival Data. London:

Chapman and Hall; 1984.

Kalbfleisch JD, Prentice RL. The statistical analysis of

failure time data. New York: John Wiley & sons Inc; 2002.

Cox DR. Regression models and life tables (with discussion).

J R Stat Soc 1972;B34:187–220.

Kosaryan M, Vahidshahi K, Karami H, Forootan MA,

Ahangari M. Survival of Thalassemia patients refferred to the

Boo Ali Sina teaching hospital, Sari, Iran. Haemoglobin

;31:453–62.

Borgna-Pignatti C, Rugolotto S, De Stefano P, Zhao H,

Cappellini MD, Del Vecchio GC, et al. Survival and

complications in patients with thalassemia major treated with

transfusion and defeoxamine. Haematologica

;89(10):1187–93.

Published

2009-03-01

Issue

Vol. 21 No. 1 (2009): JOURNAL OF AYUB MEDICAL COLLEGE, ABBOTTABAD

Section

ORIGINAL ARTICLE

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