Teladoc's (NYSE:TDOC) fourth-quarter and full-year results are out. The earnings release closes out a huge year for Teladoc. Shares have surged 69% over the past 12 months, crushing the S&P 500's paltry 1.75% gain over the same period.

While the virtual-healthcare company's momentum is undeniable, with full-year revenue surging 79% higher year over year, Teladoc disappointed when it came to its first-quarter guidance. Here's a look at where Teladoc fell short, as well as some other key metrics from the quarter.

A woman sees a doctor virtually, using her laptop

Image source: Getty Images.

1. Revenue growth

Teladoc's fourth-quarter revenue rose 59% year over year to $122.7 million. This was a deceleration from 62% revenue growth in Q3, but put the company's top line ahead of a consensus analyst estimate for revenue of $120 million.

Revenue was driven by a 36% year-over-year increase in U.S. paid visits revenue, a 155% year-over-year increase in international paid visits revenue, and $3.8 million in U.S. fee-only revenue (compared to none in the year-ago period).

2. Net loss per share

Teladoc's net loss per share was $0.35, an improvement from a loss of $0.76 in the year-ago quarter. Analysts, on average, were expecting a loss of $0.36 per share.

3. Adjusted EBITDA

Highlighting the scalability of Teladoc's business, adjusted earnings before adjusted interest, taxes, depreciation, and amortization (EBITDA) more than doubled, rising from $2.4 million in the year-ago quarter to $5.8 million in the fourth quarter of 2018.

4. Virtual visits

Visits during the quarter came in at 861,000, crushing management's guidance for visits between 720,000 and 820,000. These visits were up a whopping 86% year over year.

Excluding visits from the company's acquisition of Advance Medical, they still increased a notable 41% year over year.

5. Guidance

Teladoc CEO Jason Gorevic is optimistic about 2019, noting in the fourth-quarter earnings release that the company entered the year "with significant momentum."

"We continue to extend our leadership position by delivering the highest quality care, successfully engaging consumers, broadening our scope of services, and expanding our global geographic reach," Gorevic said.

But Teladoc's first-quarter guidance fell short of what analysts were expecting. The company said it expected first-quarter revenue between $126 million and $129 million, representing 42% year over year growth based on the midpoint of this guidance range. Analysts, on average, were expecting revenue to rise 46% year over year to $131 million.

In addition, Teladoc said it expected a first-quarter net loss per share between $0.44 and $0.46. This was worse than a consensus forecast for a net loss per share of $0.38 during the period.