High risk of Plasmodium vivax malaria following splenectomy in Papua, Indonesia

Background: Splenectomy increases the risk of severe and fatal infections; however, the risk of Plasmodium vivax malaria is unknown. We quantified the Plasmodium species-specific risks of malaria and other outcomes following splenectomy inpatients attending a hospital in Papua, Indonesia.

Methods: Records of all patients attending Mitra-Masyarakat Hospital 2004–2013 were reviewed, identifying those who underwent splenectomy. Subsequent risks of specific clinical outcomes within 12 months for splenectomized patients were compared to non-splenectomized patients from their first recorded hospital admission. In addition, patients splenectomized for trauma 2015–2016 were followed prospectively for 14 months.

Results: Of the 10774 patients hospitalized during 2004–2013, 67 underwent splenectomy. Compared to non-splenectomized inpatients, patients undergoing splenectomy had a 5-fold higher rate of malaria presentation within 12 months(adjusted hazard ratio [AHR] = 5.0 [95% confidence interval (CI): 3.4–7.3], P< .001). The AHR was 7.8 (95% CI: 5.0–12.3) for P. vivax and 3.0 (95% CI:1.7–5.4) for P. falciparum (both P < .001). Splenectomized patients had greater risk of being hospitalized for any cause (AHR = 1.8 [95% CI: 1.0–3.0],P = .037) and diarrheal (AHR = 3.5 [95% CI: 1.3–9.6], P = .016). In the14-month prospective cohort, 12 episodes of P. vivax and 6 episodes of P. falciparum were observed in 11 splenectomised patients.

Conclusions: Splenectomy is associated with a high risk of malaria, greater for P. vivax than P. falciparum. Eradication of P.vivax hypnozoites using primaquine (radical cure) and subsequent malaria prophylaxis is warranted following splenectomy in malaria-endemic areas.