The effect of comorbidity on hospital mortality in patients with SLE from an Asian tertiary hospital

Abstract

Objectives

The objective of the study was to assess the disease burden of systemic lupus erythematosus (SLE) and the usefulness of the Charlson Comorbidity Index (CCI) as risk-adjusted hospital mortality predictors in patients with SLE using a hospital administrative database.

Methods

A historical cohort study of a hospital discharge database from 2004 to 2011 was used to identify cases with SLE and comorbidity using the International Statistical Classification of Diseases and Related Health Problems, ninth revision, Australian modification (ICD-9-AM) codes.

Results

Over the eight years, 841 patients met the criteria of SLE with a hospital mortality rate of 9.2%. The hospital mortality rates (2.4%, 15.7%, 25.0%, and 30.4%, respectively, p < 0.001) and hospital length of stay (geometric mean, 3.5, 5.6, 8.8, and 7.5 days, respectively, p < 0.001) were consistently increased for patients with CCI ranging from none, low, moderate to high grade, respectively. Cox proportional hazards model analysis showed that CCI (hazard ratio (HR) 7.8 high vs. none, p < 0.001) and infectious disease (HR 2.0, p = 0.016) were significant and independent predictors of hospital mortality. Similar results were also seen with hospital length of stay by zero-truncated negative binomial regression model analysis.

Conclusion

The SLE burden is high in this population. Comorbidities and infectious disease were some of the most important contributors to hospital mortality and resource utilization.

Keywords

SLE Charlson Comorbidity Index hospital mortality length of stay ICD-9-AM

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References

Chakravarty

Bush

Manzi

Clarke

Ward

. Prevalence of adult systemic lupus erythematosus in California and Pennsylvania in 2000: Estimates obtained using hospitalization data. Arthritis Rheum 2007; 56: 2092–2094.

Balluz

Philen

Ortega

. Investigation of systemic lupus erythematosus in Nogales, Arizona. Am J Epidemiol 2001; 154: 1029–1036.

Samanta

Feehally

Roy

Nichol

Sheldon

Walls

. High prevalence of systemic disease and mortality in Asian subjects with systemic lupus erythematosus. Ann Rheum Dis 1991; 50: 490–492.

Danchenko

Satia

Anthony

. Epidemiology of systemic lupus erythematosus: A comparison of worldwide disease burden. Lupus 2006; 15: 308–318.

Chiu

Lai

. Nationwide population-based epidemiologic study of systemic lupus erythematosus in Taiwan. Lupus 2010; 19: 1250–1255.

Mok

. Do Asian patients have worse lupus? Lupus 2010; 19: 1384–1390.

Feng

Zou

Pan

. Prognostic indicators of hospitalized patients with systemic lupus erythematosus: A large retrospective multicenter study in China. J Rheumatol 2011; 38: 1289–1295.

Souza

Santo

Sato

. Trends in systemic lupus erythematosus mortality rates in the state of Sao Paulo, Brazil from 1985 to 2004. Clin Exp Rheumatol 2010; 28: 519–524.

Panopalis

Yazdany

Gillis

. Health care costs and costs associated with changes in work productivity among persons with systemic lupus erythematosus. Arthritis Rheum 2008; 59: 1788–1795.

10.

Lau

Mak

. The socioeconomic burden of SLE. Nat Rev Rheumatol 2009; 5: 400–404.

11.

Furst

Clarke

Fernandes

Bancroft

Greth

Iorga

. Incidence and prevalence of adult systemic lupus erythematosus in a large US managed-care population. Lupus 2013; 22: 99–105.

12.

Bernatsky

Boivin

Joseph

. Mortality in systemic lupus erythematosus. Arthritis Rheum 2006; 54: 2550–2557.

13.

van Doorn

Bogardus

Williams

Concato

Towle

Inouye

. Risk adjustment for older hospitalized persons: A comparison of two methods of data collection for the Charlson index. J Clin Epidemiol 2001; 54: 694–701.

14.

Deyo

Cherkin

Ciol

. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol 1992; 45: 613–619.

15.

Charlson

Pompei

Ales

MacKenzie

. A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation. J Chronic Dis 1987; 40: 373–383.

16.

Needham

Scales

Laupacis

Pronovost

. A systematic review of the Charlson comorbidity index using Canadian administrative databases: A perspective on risk adjustment in critical care research. J Crit Care 2005; 20: 12–19.

17.

de Groot

Beckerman

Lankhorst

Bouter

. How to measure comorbidity. A critical review of available methods. J Clin Epidemiol 2003; 56: 221–229.

18.

Cleves

Sanchez

Draheim

. Evaluation of two competing methods for calculating Charlson's comorbidity index when analyzing short-term mortality using administrative data. J Clin Epidemiol 1997; 50: 903–908.

19.

Quan

Couris

. Updating and validating the Charlson comorbidity index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol 2011; 173: 676–682.

20.

Sundararajan

Henderson

Perry

Muggivan

Quan

Ghali

. New ICD-10 version of the Charlson comorbidity index predicted in-hospital mortality. J Clin Epidemiol 2004; 57: 1288–1294.

21.

Statistics Singapore. Time series on population (mid-year estimates) Singapore Department of Statistics, 2012, http://www. singstat.gov.sg/stats/themes/people/hist/popn.html (2012, accessed 20 February 2013).

22.

Singapore General Hospital. Types of wards in SGH. Singapore General Hospital, http://www.sgh.com.sg/Patient-Services/Charges-Payment/Pages/types-wards.aspx (2013, accessed 15 October 2013).

23.

Bernatsky

Linehan

Hanly

. The accuracy of administrative data diagnoses of systemic autoimmune rheumatic diseases. J Rheumatol 2011; 38: 1612–1616.

24.

Charlson

Szatrowski

Peterson

Gold

. Validation of a combined comorbidity index. J Clin Epidemiol 1994; 47: 1245–1251.

25.

Jepsen

Vilstrup

Andersen

Lash

Sorensen

. Comorbidity and survival of Danish cirrhosis patients: A nationwide population-based cohort study. Hepatology 2008; 48: 214–220.

26.

Cameron

Trivedi

. Regression analysis of count data, Cambridge: Cambridge University Press, 1998.

27.

Lopez

Davidson

Beeby

Egger

Isenberg

. Lupus disease activity and the risk of subsequent organ damage and mortality in a large lupus cohort. Rheumatology (Oxford) 2012; 51: 491–498.

28.

Teh

Ling

. Causes and predictors of mortality in hospitalized lupus patient in Sarawak General Hospital, Malaysia. Lupus 2013; 22: 106–111.

29.

Yeap

Chow

Manivasagar

Veerapen

Wang

. Mortality patterns in Malaysian systemic lupus erythematosus patients. Med J Malaysia 2001; 56: 308–312.

30.

Zonana-Nacach

Yañez

Jiménez-Balderas

Camargo-Coronel

. Disease activity, damage and survival in Mexican patients with acute severe systemic lupus erythematosus. Lupus 2007; 16: 997–1000.

31.

Edwards

Lian

Badsha

Teh

Arden

Chng

. Hospitalization of individuals with systemic lupus erythematosus: Characteristics and predictors of outcome. Lupus 2003; 12: 672–676.

32.

Krishnan

. Hospitalization and mortality of patients with systemic lupus erythematosus. J Rheumatol 2006; 33: 1770–1774.

33.

Ward

. Development and testing of a systemic lupus-specific risk adjustment index for in-hospital mortality. J Rheumatol 2000; 27: 1408–1413.

34.

Jonsen

Clarke

Joseph

. Association of the Charlson comorbidity index with mortality in systemic lupus erythematosus. Arthritis Care Res (Hoboken) 2011; 63: 1233–1237.

35.

Liang

Lin

Wang

. Influence of predialysis comorbidity and damage accrual on mortality in lupus patients treated with peritoneal dialysis. Lupus 2010; 19: 1210–1218.

36.

Tetsche

Dethlefsen

Pedersen

Sorensen

Norgaard

. The impact of comorbidity and stage on ovarian cancer mortality: A nationwide Danish cohort study. BMC Cancer 2008; 8: 31–31.

37.

Thombs

Singh

Halonen

Diallo

Milner

. The effects of preexisting medical comorbidities on mortality and length of hospital stay in acute burn injury: Evidence from a national sample of 31,338 adult patients. Ann Surg 2007; 245: 629–634.

38.

Yang

Hsann

Lim

Ong

. The effect of comorbidity and age on hospital mortality and length of stay in patients with sepsis. J Crit Care 2010; 25: 398–405.

39.

Bertsias

Ioannidis

Boletis

. EULAR recommendations for the management of systemic lupus erythematosus. Report of a Task Force of the EULAR Standing Committee for International Clinical Studies Including Therapeutics. Ann Rheum Dis 2008; 67: 195–205.

40.

Kang

Hwang

Chang

Chou

Tsai

. Characteristics of comorbidities and costs among patients who died from systemic lupus erythematosus in Taiwan. Arch Med Sci 2012; 8: 690–696.

41.

Mok

. Epidemiology and survival of systemic lupus erythematosus in Hong Kong Chinese. Lupus 2011; 20: 767–771.

42.

Smith Sehdev

Hutchins

. Problems with proper completion and accuracy of the cause-of-death statement. Arch Intern Med 2001; 161: 277–284.