Modifies provisions relating to the collateral source rule

HB 1646 modifies Missouri's collateral source rule for personal injury cases. It replaces the previous rule by allowing defendants to deduct payments made toward a plaintiff's medical costs before trial from any later judgment. The bill also restricts evidence in court to the actual amount paid for medical care (after discounts or write-offs), not the full billed amount. This directly affects plaintiffs seeking compensation, defendants in injury lawsuits, and healthcare providers billing for services. The change ensures defendants aren't charged for medical costs already covered by the plaintiff's insurer or other sources.