Spineline - May/June 2014

Patients with negative claim payments were excluded from the analysis, along with those with abnormal length of stays (less than two days or greater than 60 days). We then totaled all inpatient and outpatient claims for each patient over a 30–, 60– and 90–day window following each inpatient stay, including any spine-related readmissions or reoperations within the time frame considered. We summarize the data separately for each DRG considered.

Note also that, for any given follow-up period (ie, 30, 60 and 90 days), we included all claims incurred during this time frame. Such claims may therefore include outpatient costs not related to the initial spine surgery and thus may overestimate the true cost of care. However, we would anticipate that any non–spine-related outpatient costs would be relatively small compared to the overall inpatient costs and the cumulative 30–, 60- and 90-day costs.

All analyses were performed using Stata 13. 1 (StataCorp LP, College Station, TX).

Results

Medicare claim payment data were available for 57,062 patients undergoing surgery with primary DRGs of 453-460.

Patients were predominantly female (62%), and the average length of stay for the initial spine surgery was six days (SD= 3. 8, range 2 to 60). A total of 1,243 patients has a subsequent spine surgery following the initial surgery within 2009. Of these, 864 occurred within 90 days following the initial surgery (this would include operations associated with staged procedures). The average payment for the initial surgical claim was $28,751 (SD= $17,023), constituting the majority of total 90–day costs (97%). Patients had an average of three postoperative Medicare claims within 90 days following surgery, with an average payment of $240 per claim.

In total, the average 90–day cost of care for DRG 453 ( combined anterior/posterior spinal fusion with major complications or comorbidities) was $78,476; while the average 90–day cost of care for DRG 460 (noncervical spinal fusion without any major complications or comorbidities) was $24,131. The total Medicare reimbursements for each DRG and subsequent 30–, 60– and 90–days postdischarge are summarized in Table 1. Averaged across all DRGs considered, the 90–day cost of care for patients with a readmission or additional operation averaged $66,620 compared to $29,281 for patients without a readmission within 90 days, as presented in Table 2.

Table 1. 30–, 60–, and 90–Day Costs of Care following
Initial Complex Spine Fusion Surgery including Any
Related Readmissions
DRG Initial Surgery 30 Days 60 Days 90 Days

453 $77,160 ($27,427) $78,244 ($28,285) $79,069 ($28,655) $79,782 ($28,921)

454 $52,454 ($22,765) $52,979 ($23,372) $53,496 ($23,717) $53,906 ($23,871)

455 $37,028 ($15,004) $37,402 ($15,225) $37,713 ($15,423) $37,993 ($15,587)

456 $67,560 ($27,525) $68,600 ($28,356) $69,885 ($29,072) $70,820 ($29,597)

457 $44,700 ($21,551) $45,728 ($22,920) $46,472 ($23,452) $47,099 ($24,133)

458 $33,550 ($14,335) $34,173 ($15,471) $34,840 ($16,026) $35,082 ($16,081)

459 $39,619 ($18,386) $40,164 ($18,804) $40,751 ($19,224) $41,207 ($19,439)

460 $23,579 ($9,426) $23,911 ($9,815) $24,209 ($10,243) $24,459 ($10,431)

Total $28,751 ($17,023) $29,163 ($17,499)$29,538 ($17,906)$29,841 ($18,151)

Note: Standard deviations in parentheses.

Table 2. 90–Day Cost of Care following Complex Spine Fusion Surgery for Patients with and without Readmissions within 90 Days following Initial Surgery