Table 1.

Case–control assignment for cohort using two different criteria

Clinically determined CIO (N = 229)Geometric mean of hearing thresholds (N = 229)
Moderate–severe CIO (N = 37)aModerate–profound hearing loss (N = 33)a
CasesAudiogram configuration consistent with CIO; hearing threshold ≥25 dB at frequencies <8 kHzGeometric mean hearing thresholds >40 dB
ControlsNo CIO (N = 153)b,cNo hearing loss (N = 167)b,c
Audiograms show no evidence of ototoxicity or audiogram configurations show that hearing loss is clearly ascribable to a cause other than CIO (e.g., flat or upsloping sensorineural hearing loss)Geometric mean hearing thresholds ≤25 dB
ExclusionsMild CIO (N = 20)Mild hearing loss (N = 19)
Audiogram configuration consistent with CIO; hearing threshold ≥25 dB at frequencies ≥8 kHzGeometric mean hearing threshold 26–40 dB
Ambiguous (N = 19)Asymmetrical hearing lossd (N = 10)
Audiogram configuration does not provide sufficient information to allow for classification as cases or controls (e.g., hearing loss possibly due to aging)Audiograms show ear asymmetry (geometric mean difference >20 dB between the two ears)
  • Abbreviations: CIO: cisplatin-induced ototoxicity, dB: decibels, kHz: kilohertz.

  • aTwenty-six individuals were assigned case status by both assignment systems.

  • bOne hundred forty-four individuals were assigned control status by both assignment systems.

  • cGenotyping failed in two individuals.

  • dTo ensure consistency between the current cohort and the cohort utilized by Wheeler et al. (7), which reported only two patients with ear asymmetry, we excluded patients with ear asymmetry.