Table 1.

Medicare claims brain metastasis classification accuracy

PrimaryPredictedTrueSensPPVSpecKappa
Algorithm: synchronous
LungOverall5,1006,7890.580.770.980.63 (0.62–0.64)
Adenocarcinoma2,1032,8060.590.790.980.63 (0.62–0.65)
Carcinoma4035710.570.800.980.62 (0.59–0.66)
NSCLC5067450.560.820.980.62 (0.58–0.65)
Other5727840.580.800.990.65 (0.62–0.68)
SCLC8721,1440.590.780.970.62 (0.60–0.65)
Squamous6447390.570.660.990.60 (0.56–0.63)
BreastOverall1962030.460.471.000.46 (0.40–0.53)
Her2−/Hr+103860.410.341.000.37 (0.28–0.46)
Her2+/Hr(+/−)27310.480.561.000.51 (0.36–0.67)
Other38500.440.581.000.50 (0.37–0.63)
Triple (−)28360.580.751.000.65 (0.52–0.79)
SkinOverall1522300.550.831.000.66 (0.60–0.71)
MMJN**0.430.601.000.50 (0.15–0.85)
Nevi and melanomas1342060.540.831.000.65 (0.59–0.71)
Other13*0.710.921.000.79 (0.64–0.95)
Algorithm: Lifetime
LungOverall9,1386,7890.650.480.920.49 (0.48–0.50)
Adenocarcinoma3,6302,8060.650.500.910.50 (0.48–0.51)
Carcinoma5755710.630.620.950.57 (0.53–0.61)
NSCLC8047450.610.570.920.52 (0.49–0.55)
Other1,0287840.650.500.950.52 (0.49–0.55)
SCLC1,8631,1440.670.410.840.40 (0.38–0.43)
Squamous1,2387390.640.380.950.45 (0.42–0.48)
BreastOverall9672030.570.120.990.19 (0.16–0.22)
Her2-/Hr+430860.530.110.990.18 (0.13–0.22)
Her2+/Hr(+/−)181310.680.120.970.19 (0.12–0.26)
Other144500.540.190.990.27 (0.19–0.36)
Triple (−)212360.580.100.960.16 (0.10–0.22)
SkinOverall6582300.660.230.980.33 (0.29–0.37)
MMJN114*0.710.040.990.08 (0.01–0.15)
Nevi and melanomas4982060.650.270.970.36 (0.32–0.41)
Other46*0.820.300.950.42 (0.27–0.57)
  • For Medicare claims data algorithms identifying synchronous and lifetime BMs based on the presence of a diagnosis code for secondary cancer of the CNS and a procedure code indicating intracranial imaging within sixty days of the other, this table shows classification accuracy compared with a SEER SBM gold standard. The rows under “Algorithm: Synchronous” represent such an algorithm with the additional criteria that codes must have occurred within 60 days of primary cancer diagnosis, whereas “Algorithm: Lifetime” indicates that codes may have occurred at anytime in Medicare claims. “Sens” refers to sensitivity; “spec”, specificity; PPV, positive predictive value. An asterisk (“*”) represents values that are suppressed to avoid reporting data from 1 to 11 cases.