Anticoagulation in a Fall-Prone Elder with New AF
A 79-year-old woman is brought to clinic after a mechanical fall at home; she struck her head but has no loss of consciousness, no focal deficit, and a normal non-contrast head CT. Her past history includes hypertension, type 2 diabetes with an eGFR of 38 mL/min/1.73 m2, and mild cognitive impairment (MMSE 24/30). She lives alone; her daughter visits twice weekly. A routine ECG today shows new atrial fibrillation at 88 bpm. CHA2DS2-VASc is 6 (age, sex, hypertension, diabetes, prior TIA 3 years ago). She has fallen twice in the past year, both without injury. She takes amlodipine and metformin only. She asks whether she 'has to take a blood thinner' because she is afraid of bleeding.
1. Estimate her stroke risk and bleeding risk, and decide whether anticoagulation should be offered. Justify your decision in terms of absolute risk, not just scores.
Read the worked answer
Stroke risk: CHA2DS2-VASc 6 corresponds to an annual ischemic stroke risk in the range of roughly 6–10% without anticoagulation; this is high. Bleeding risk: HAS-BLED is elevated (age >65, renal impairment, prior falls are not formally scored but are clinically relevant), but a high HAS-BLED score is a prompt to modify reversible factors and monitor - it is not a reason to withhold anticoagulation when stroke risk is this high.
Decision: Offer anticoagulation. The absolute stroke reduction (roughly 60–70% relative reduction, i.e., several percentage points per year) generally outweighs the absolute increase in major bleeding (typically ~1%/year or less for DOACs). A fall rate of twice per year without injury is a low annual risk of subdural hematoma relative to the stroke burden. Document a shared decision, address fall prevention (home safety, vision, gait/balance, review of sedating medications), and reassess at follow-up.
2. Which anticoagulant would you choose for this patient, and what dosing considerations apply given her renal function?
Read the worked answer
Preferred: A direct oral anticoagulant (apixaban is often favored in frail elderly patients with renal impairment because of its favorable bleeding profile and less renal clearance).
Renal dosing:
- Apixaban: reduce to 2.5 mg twice daily if two of three criteria are met: age ≥80, weight ≤60 kg, creatinine ≥1.5 mg/dL. At age 79 with eGFR 38, dose depends on weight and creatinine - check both; if only one criterion is met, use 5 mg twice daily. Avoid if CrCl <15.
- Rivaroxaban: 15 mg daily if CrCl 15–50; avoid if <15.
- Dabigatran: largely renally cleared; avoid if CrCl <30.
- Warfarin remains an option but requires INR monitoring and has higher intracranial hemorrhage risk; it is reasonable if DOACs are unaffordable or contraindicated.
Also review drug interactions (she is on amlodipine - no significant interaction) and confirm no severe thrombocytopenia or active bleeding.
3. She starts apixaban. Six weeks later she has another fall with a scalp hematoma but no neurologic symptoms. What is your management?
Read the worked answer
Assess for intracranial hemorrhage first. A fall with head strike while anticoagulated warrants a low threshold for non-contrast head CT, particularly with any headache, vomiting, confusion, or focal deficit. If CT is negative and she is neurologically intact, she can generally continue anticoagulation.
Do not stop anticoagulation reflexly - discontinuation restores the high stroke risk, and the bleed risk from a minor fall is lower than the stroke risk. Instead:
- Reassess fall etiology (orthostatic vitals, vision, gait, home hazards, review of antihypertensives causing orthostasis).
- Consider a home safety evaluation and physical therapy.
- Document a renewed shared decision with the patient and daughter.
- Reassess renal function periodically (eGFR can drift).
If she had a significant intracranial hemorrhage, reversal and temporary interruption would be considered, with a multidisciplinary discussion about resumption.