Predictors for splenectomy among patients with primary chronic immune thrombocytopenia: a population-based cohort study from Denmark


We conducted a nationwide cohort study of adult Danish patients with primary chronic immune thrombocytopenia (cITP) to examine selected patient and clinical characteristics as predictors for splenectomy. We analyzed data from the Danish National Patient Registry and patient medical records from 1996 to 2007. Using Cox regression analyses, we calculated incidence rate ratios (IRRs) and associated 95% confidence intervals (CI) for splenectomy. We included 371 adult cITP patients. Of these, 87 patients (23%) underwent a splenectomy during a median of 3.6 years of follow-up. The majority (84%) of cITP patients who underwent splenectomy had splenectomy within the first year after cITP diagnosis. Predictors for splenectomy included age ≤75 years (adjusted 1-year IRR = 6.79 (95% CI, 2.10–21.90)) at least one platelet count ≤30 × 109/L (i.e., high disease activity; adjusted 1-year IRR = 2.67 (95% CI, 1.37–5.22)) during follow-up and year of cITP diagnosis in early period (1996–2001; adjusted 1 year IRR = 2.37 (95% CI, 1.46–3.85)). Presence of chronic comorbidity was associated with lower rates of splenectomy (adjusted 1 year IRR = 0.58 (95% CI, 0.33–1.05)). Our findings suggest that high disease activity and absence of chronic comorbidity may be associated with higher rates of splenectomy, and that contraindications for splenectomy (i.e., patients’ perceived frailty) cause the physicians to use the procedure cautiously.

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This study was supported by Amgen and received unrestricted grants from the Karen Elise Jensen Foundation.

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Correspondence to Annette Østergaard Jensen.



Translation of disease categories of chronic diseases into discharge diagnoses in ICD-8 and ICD-10

Disease category Diseases ICD-8 ICD-10
Cardiopulmonary disease Acute myocardial infarction, congestive heart disease, peripheral vascular disease and cerebrovascular disease, emphysema, asthma, and chronic obstructive lung disease 410; 427.09; 427.10; 427.11; 427.19; 428.99; 782.49; 440–445; 430–438. I21–I23; I50; I11.0; I13.0; I13.2; I70–I74; I77; I60–I69; G45–G46.
490–493; 515–518 J40–J47; J60–J67; J68.4; J70.1; J70.3; J84.1; J92.0; J96.1; J98.2; J98.3
Connective tissue disease Diffuse connective tissue disease, rheumatoid arthritis and other inflammatory polyarthropathies and polymyalgia rheumatica 712; 716; 734; 446; 135.99 M05; M06; M08; M09; M30–M36; D86
Moderate to severe renal disease Glomerulonephritis, nephropathies and end-stage renal disease 403; 404; 580–583; 584; 590.09; 593.19; 753.10–753.19; 792 I12; I13; N00–N05; N07; N11; N14; N17–N19; Q61
Hepatic disorder   570–577 K70–K77
Diabetes   249, 250 E10, E12, E11

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Jensen, A.Ø., Nørgaard, M., Engebjerg, M.C. et al. Predictors for splenectomy among patients with primary chronic immune thrombocytopenia: a population-based cohort study from Denmark. Ann Hematol 90, 207–212 (2011).

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  • Chronic immune thrombocytopenia
  • Splenectomy
  • Cohort study
  • Risk