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Table 2 Hydrocephalus incidence rates

From: The incidence of hydrocephalus among patients with and without spinal muscular atrophy (SMA): Results from a US electronic health records study

  Rate per 100,000 PMs among SMA cases (N = 5354) (IR [95% CI]) Rate per 100,000 PMs among non-SMA matched controls (N = 5354) (IR [95% CI]) Incidence rate ratioa (95% CI)
Incident hydrocephalus events 42 9  
Overall incidence rate 15.5 (11.2–20.9) 3.3 (1.5–6.3) 4.7 (2.4–10.2)
Incidence rate by sex
 Female 13.9 (8.2–21.9) 2.3 (0.5–6.7) 6.0 (1.9–25.7)
 Male 17.0 (10.9–25.3) 4.2 (1.6–9.2) 4.0 (1.7–10.8)
Incidence rate by age at index date (years)
 < 1 50.7 (6.1–183.3) 0.00 N/C
 1 to < 2 55.5 (11.4–162.1) 0.00 N/C
 2 to < 13 17.3 (5.6–40.4) 3.4 (0.1–19.1) 5.1 (0.7–120.1)
 13 to ≤ 20 16.6 (3.4–48.5) 5.5 (0.1–30.7) 3.0 (0.3–79.3)
 21 to ≤ 30 9.8 (1.2–35.5) 0.00 N/C
 31 to ≤ 40 0.00 0.00 N/C
 41 to ≤ 50 2.8 (0.1–15.9) 2.8 (0.1–15.9) 1.0 (0.0–39.0)
 > 50 21.7 (14.2–31.8) 5.0 (1.8–10.9) 4.4 (1.9–11.6)
  1. CI confidence interval, IR incidence rate, IRR incidence rate ratio, N/C not calculable, PM person-month, SMA spinal muscular atrophy
  2. a95% CI for IRR not calculated due to small sample size